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  • Solaris OpenStack Horizon customizations

    - by GirishMoodalbail-Oracle
    In Oracle Solaris OpenStack Havana, we have customized the Horizon BUI by modifying existing dashboard and panels to reflect only those features that we support. The modification mostly involves:  --  disabling an widget (checkbox, button, textarea, and so on) --  removal of a tab from a panel --  removal of options from pull-down menus The following table lists the customizations that we have made. |-----------------------------+-----------------------------------------------------| | Where                       | What                                                | |-----------------------------+-----------------------------------------------------| | Project => Instances =>     | Post-Creation tab is removed.                       | | Launch Instance             |                                                     | |                             |                                                     | | Project => Instances =>     | Security Groups tab is removed.                     | | Actions => Edit Instance    |                                                     | |                             |                                                     | | Project => Instances =>     | Console tab is removed.                             | | Instance Name               |                                                     | |                             |                                                     | | Project => Instances =>     | Following actions Console, Edit Security Groups,    | | Actions                     | Pause Instance, Suspend Instance, Resize Instance,  | |                             | Rebuild Instance, and Migrate Instance are removed. | |                             |                                                     | | Project =>                  | Security Groups tab is removed.                     | | Access and Security         |                                                     | |                             |                                                     | | Project =>                  | Create Volume action is removed.                    | | Images and Snapshots =>     |                                                     | | Images => Actions           |                                                     | |                             |                                                     | | Project => Networks =>      | Admin State is disabled and its value is always     | | Create Network              | true.                                               | |                             |                                                     | | Project => Networks =>      | Disable Gateway checkbox is disabled, and its       | | Create Network =>           | value is always false.                              | | Subnet                      |                                                     | |                             |                                                     | | Project => Networks =>      | Allocation Pools and Host Routes text area are      | | Create Network =>           | disabled.                                      | | Subnet Detail               |                                                     | |                             |                                                     | | Project => Networks =>      | Edit Subnet action is removed.                      | | Network Name => Subnet =>   |                                                     | | Actions                     |                                                     | |                             |                                                     | | Project => Networks =>      | Edit Port action is removed.                        | | Network Name => Ports =>    |                                                     | | Actions                     |                                                     | |                             |                                                     | | Admin => Instnaces =>       | Following actions Console, Pause Instance,          | | Actions                     | Suspend Instance, and Migrate Instance are removed. | |                             |                                                     | | Admin => Networks =>        | Edit Network action is removed                      | | Actions                     |                                                     | |                             |                                                     | | Admin => Networks =>         | Edit Subnet action is removed                       | | Subnets => Actions          |                                                     | |                             |                                                     | | Admin => Networks =>         | Edit Port action is removed                         | | Ports => Actions            |                                                     | |                             |                                                     | | Admin => Networks =>         | Admin State and Shared check box are disabled.      | | Create Network              | Network's Admin State is always true, and Shared is | |                             | always false.                                       | |                             |                                                     | | Admin => Networks =>        | Admin State check box is disabled and its value     | | Network Name => Create Port | is always true.                                     | |-----------------------------+-----------------------------------------------------|

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  • How to use Bonjour?

    - by Roman
    First, what exactly Bonjour does (pleas read my guesses written bellow)? Here I found out that Bonjour enables automatic discovery of computers, devices, and services on IP networks. But I thought that it not only "discovers devices on IP network" it also creates an IP network by assigning IP addresses to devices where Bonjour is running. Am I right? And I still miss the essence. Does it work in the following way? First I connect devices (for example laptops) physically so that they potentially can communicate with each other. Then, let say, on some laptops I have Bonjour running and then, as a consequence, these laptops assign IP addresses to them self in automatic way. So, laptops (where Bonjour is running) build an IP network. Does it work in this way? Or may be a computer running Bonjour is not considered as a service and it does not broadcast itself just because Bonjour is running on this computer. I mean that the applications running on the computers need to use Bonjour to broadcast themself. So, it is applications that broadcast themself (not computers) and it is not done automatically (application needs to broadcast themself explicitly). Is it right? How exactly my application can broadcast itself? Can I use command line to register an service (so that all applications using Bonjour knows that a new service appeared)? Further, I would like to have an application which use the IP network created by Bonjour. For that my application needs to know which devices/services are present in the network. In more details, my application needs to have a list of services. Each service in the list should have a name, the IP address where it is running and the port which is used by the application. Can Bonjour provide this information in some way? If it is the case, how exactly it works. How my program can get this information from Bonjour? Can my program read some file created by Bonjour and containing the above mentioned information? Can I use some commands in command line to retrieve this information? I have a special interest in accessing the information about services from files, environment variables or commands in command line. These options seems to me to be the simplest! Since in these case I do not need to use any additional libraries to communicate with Bonjour from a particular programming language. P.S. Pleas ask questions if something is not clear in my question. I will try to formulate my question in a more clear way. P.P.S. I use Windows 7. ADDED: I plan to write my applications in PHP. Every computer should run a Apache web server. And I want to use Bonjour to help computer discover each other (computers are working in a local network).

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  • Cannot join Win7 workstations to Win2k8 domain

    - by wfaulk
    I am trying to connect a Windows 7 Ultimate machine to a Windows 2k8 domain and it's not working. I get this error: Note: This information is intended for a network administrator. If you are not your network's administrator, notify the administrator that you received this information, which has been recorded in the file C:\Windows\debug\dcdiag.txt. DNS was successfully queried for the service location (SRV) resource record used to locate a domain controller for domain "example.local": The query was for the SRV record for _ldap._tcp.dc._msdcs.example.local The following domain controllers were identified by the query: dc1.example.local dc2.example.local However no domain controllers could be contacted. Common causes of this error include: Host (A) or (AAAA) records that map the names of the domain controllers to their IP addresses are missing or contain incorrect addresses. Domain controllers registered in DNS are not connected to the network or are not running. The client is in an office connected remotely via MPLS to the data center where our domain controllers exist. I don't seem to have anything blocking connectivity to the DCs, but I don't have total control over the MPLS circuit, so it's possible that there's something blocking connectivity. I have tried multiple clients (Win7 Ultimate and WinXP SP3) in the one office and get the same symptoms on all of them. I have no trouble connecting to either of the domain controllers, though I have, admittedly, not tried every possible port. ICMP, LDAP, DNS, and SMB connections all work fine. Client DNS is pointing to the DCs, and "example.local" resolves to the two IP addresses of the DCs. I get this output from the NetLogon Test command line utility: C:\Windows\System32>nltest /dsgetdc:example.local Getting DC name failed: Status = 1355 0x54b ERROR_NO_SUCH_DOMAIN I have also created a separate network to emulate that office's configuration that's connected to the DC network via LAN-to-LAN VPN instead of MPLS. Joining Windows 7 computers from that remote network works fine. The only difference I can find between the two environments is the intermediate connectivity, but I'm out of ideas as to what to test or how to do it. What further steps should I take? (Note that this isn't actually my client workstation and I have no direct access to it; I'm forced to do remote hands access to it, which makes some of the obvious troubleshooting methods, like packet sniffing, more difficult. If I could just set up a system there that I could remote into, I would, but requests to that effect have gone unanswered.) 2011-08-25 update: I had DCDIAG.EXE run on a client attempting to join the domain: C:\Windows\System32>dcdiag /u:example\adminuser /p:********* /s:dc2.example.local Directory Server Diagnosis Performing initial setup: Ldap search capabality attribute search failed on server dc2.example.local, return value = 81 This sounds like it was able to connect via LDAP, but the thing that it was trying to do failed. But I don't quite follow what it was trying to do, much less how to reproduce it or resolve it. 2011-08-26 update: Using LDP.EXE to try and make an LDAP connection directly to the DCs results in these errors: ld = ldap_open("10.0.0.1", 389); Error <0x51: Fail to connect to 10.0.0.1. ld = ldap_open("10.0.0.2", 389); Error <0x51: Fail to connect to 10.0.0.2. ld = ldap_open("10.0.0.1", 3268); Error <0x51: Fail to connect to 10.0.0.1. ld = ldap_open("10.0.0.2", 3268); Error <0x51: Fail to connect to 10.0.0.2. This would seem to point fingers at LDAP connections being blocked somewhere. (And 0x51 == 81, which was the error from DCDIAG.EXE from yesterday's update.) I could swear I tested this using TELNET.EXE weeks ago, but now I'm thinking that I may have assumed that its clearing of the screen was telling me that it was waiting and not that it had connected. I'm tracking down LDAP connectivity problems now. This update may become an answer.

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  • How to debug solve 500 Internal error aws micro ec2 with suexec, Apache and php CGi

    - by Oudin
    I'm running WordPress multi-site on an amazon micro ec2 with suexec, Apache and php CGi On Ubuntu 12.04 However I've been experiencing a lot of Internal server 500 errors and I'm in the process of debugging it to find a solution. I've posted my error logs below example.com error.log: [Fri Oct 26 10:10:08 2012] [warn] [client 23.23.xxx.xx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server [Fri Oct 26 10:10:08 2012] [error] [client 23.23.xxx.xx] Premature end of script headers: wp-cron.php [Fri Oct 26 10:50:04 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/ [Fri Oct 26 10:50:04 2012] [error] [client 190.213.xxx.xxx] Premature end of script headers: admin.php, referer: https://www.example.com/wp-admin/ [Fri Oct 26 10:58:14 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:58:15 2012] [error] [client 190.213.xxx.xxx] Premature end of script headers: admin-ajax.php, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:58:56 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:58:57 2012] [error] [client 190.213.xxx.xxx] Premature end of script headers: plugins.php, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:59:18 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 10:59:18 2012] [error] [client 190.213.xxx.xxx] Premature end of script headers: admin-ajax.php, referer: https://www.example.com/wp-admin/network/index.php [Fri Oct 26 11:01:49 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server, referer: https://www.example.com/wp-admin/ [Fri Oct 26 11:01:49 2012] [warn] [client 190.213.xxx.xxx] (104)Connection reset by peer: mod_fcgid: ap_pass_brigade failed in handle_request_ipc function, referer: https://www.example.com/wp-admin/ Apache Log: php (pre-forking): Cannot allocate memory php (pre-forking): Cannot allocate memory Recipient names must be specified Recipient names must be specified php (pre-forking): Cannot allocate memory php (pre-forking): Cannot allocate memory php (pre-forking): Cannot allocate memory [Fri Oct 26 10:49:33 2012] [warn] mod_fcgid: cleanup zombie process 2852 [Fri Oct 26 10:49:33 2012] [warn] mod_fcgid: cleanup zombie process 2851 [Fri Oct 26 10:49:33 2012] [warn] mod_fcgid: cleanup zombie process 2853 [Fri Oct 26 10:58:22 2012] [warn] mod_fcgid: process 2892 graceful kill fail, sending SIGKILL php (pre-forking): Cannot allocate memory [Fri Oct 26 10:59:21 2012] [warn] mod_fcgid: process 2894 graceful kill fail, sending SIGKILL [Fri Oct 26 10:59:25 2012] [warn] mod_fcgid: process 2866 graceful kill fail, sending SIGKILL suexec.log: [2012-10-25 16:05:36]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:09:38]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:09:51]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:14:03]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:14:06]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 18:14:35]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 20:20:27]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 20:20:29]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 20:20:31]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 21:42:12]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-25 22:56:50]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 02:34:43]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 04:25:07]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 06:35:19]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 06:40:05]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 07:22:45]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 10:10:05]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 10:49:24]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi [2012-10-26 10:49:24]: uid: (1002/username) gid: (1002/username) cmd: php-fcgi based on the logs can any determine what might be the cause of this? Thinking that it might be the micro instance I'm thinking of upgrading to a small. Any help would be greatly appreciated.

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  • got VPN l2l connect between a site & HQ but not traffice using ASA5505 on both ends

    - by vinlata
    Hi, Could anyone see what did I do wrong here? this is one configuration of site1 to HQ on ASA5505, I can get connected but seems like no traffic going (allowed) between them, could it be a NAT issue? any helps would much be appreciated Thanks interface Vlan1 nameif inside security-level 100 ip address 172.30.205.1 255.255.255.0 ! interface Vlan2 nameif outside security-level 0 ip address pppoe setroute ! interface Ethernet0/0 switchport access vlan 2 ! interface Ethernet0/1 ! interface Ethernet0/2 shutdown ! interface Ethernet0/3 shutdown ! interface Ethernet0/4 shutdown ! interface Ethernet0/5 shutdown ! interface Ethernet0/6 shutdown ! interface Ethernet0/7 shutdown ! passwd .dIuXDIYzD6RSHz7 encrypted ftp mode passive dns server-group DefaultDNS domain-name errg.net object-group network HQ network-object 172.22.0.0 255.255.0.0 network-object 172.22.0.0 255.255.128.0 network-object 172.22.0.0 255.255.255.128 network-object 172.22.1.0 255.255.255.128 network-object 172.22.1.0 255.255.255.0 access-list inside_access_in extended permit ip any any access-list outside_access_in extended permit icmp any any echo-reply access-list outside_20_cryptomap extended permit ip 172.30.205.0 255.255.255.0 o bject-group HQ access-list inside_nat0_outbound extended permit ip 172.30.205.0 255.255.255.0 o bject-group HQ access-list policy-nat extended permit ip 172.30.205.0 255.255.255.0 172.22.0.0 255.255.0.0 pager lines 24 logging asdm informational mtu inside 1500 mtu outside 1500 icmp unreachable rate-limit 1 burst-size 1 no asdm history enable arp timeout 14400 nat-control global (outside) 1 interface nat (inside) 0 access-list inside_nat0_outbound nat (inside) 1 0.0.0.0 0.0.0.0 static (inside,outside) 172.30.205.0 access-list policy-nat access-group inside_access_in in interface inside access-group outside_access_in in interface outside timeout xlate 3:00:00 timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02 timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00 timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00 timeout uauth 0:05:00 absolute username errgadmin password Os98gTdF8BZ0X2Px encrypted privilege 15 http server enable http 64.42.2.224 255.255.255.240 outside http 172.22.0.0 255.255.0.0 outside no snmp-server location no snmp-server contact snmp-server enable traps snmp authentication linkup linkdown coldstart crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac crypto map outside_map 190 match address outside_20_cryptomap crypto map outside_map 190 set pfs crypto map outside_map 190 set peer 66.7.249.109 crypto map outside_map 190 set transform-set ESP-3DES-SHA crypto map outside_map 190 set phase1-mode aggressive crypto map outside_map interface outside crypto isakmp enable outside crypto isakmp policy 30 authentication pre-share encryption 3des hash sha group 2 lifetime 86400 crypto isakmp policy 65535 authentication pre-share encryption 3des hash sha group 2 lifetime 86400 crypto isakmp nat-traversal 190 crypto isakmp ipsec-over-tcp port 10000 tunnel-group 66.7.249.109 type ipsec-l2l tunnel-group 66.7.249.109 ipsec-attributes pre-shared-key * telnet timeout 5 ssh 172.30.205.0 255.255.255.0 inside ssh 172.22.0.0 255.255.0.0 outside ssh 64.42.2.224 255.255.255.240 outside ssh 172.25.0.0 255.255.128.0 outside ssh timeout 5 console timeout 0 management-access inside vpdn group PPPoEx request dialout pppoe vpdn group PPPoEx localname [email protected] vpdn group PPPoEx ppp authentication pap vpdn username [email protected] password ********* dhcpd address 172.30.205.100-172.30.205.131 inside dhcpd dns 172.22.0.133 68.94.156.1 interface inside dhcpd wins 172.22.0.133 interface inside dhcpd domain errg.net interface inside dhcpd enable inside ! ! class-map inspection_default match default-inspection-traffic ! ! policy-map type inspect dns preset_dns_map parameters message-length maximum 512 policy-map global_policy class inspection_default inspect dns preset_dns_map inspect ftp inspect h323 h225 inspect h323 ras inspect netbios inspect rsh inspect rtsp inspect skinny inspect esmtp inspect sqlnet inspect sunrpc inspect tftp inspect sip inspect xdmcp ! end

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  • The Incremental Architect&rsquo;s Napkin - #5 - Design functions for extensibility and readability

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/24/the-incremental-architectrsquos-napkin---5---design-functions-for.aspx The functionality of programs is entered via Entry Points. So what we´re talking about when designing software is a bunch of functions handling the requests represented by and flowing in through those Entry Points. Designing software thus consists of at least three phases: Analyzing the requirements to find the Entry Points and their signatures Designing the functionality to be executed when those Entry Points get triggered Implementing the functionality according to the design aka coding I presume, you´re familiar with phase 1 in some way. And I guess you´re proficient in implementing functionality in some programming language. But in my experience developers in general are not experienced in going through an explicit phase 2. “Designing functionality? What´s that supposed to mean?” you might already have thought. Here´s my definition: To design functionality (or functional design for short) means thinking about… well, functions. You find a solution for what´s supposed to happen when an Entry Point gets triggered in terms of functions. A conceptual solution that is, because those functions only exist in your head (or on paper) during this phase. But you may have guess that, because it´s “design” not “coding”. And here is, what functional design is not: It´s not about logic. Logic is expressions (e.g. +, -, && etc.) and control statements (e.g. if, switch, for, while etc.). Also I consider calling external APIs as logic. It´s equally basic. It´s what code needs to do in order to deliver some functionality or quality. Logic is what´s doing that needs to be done by software. Transformations are either done through expressions or API-calls. And then there is alternative control flow depending on the result of some expression. Basically it´s just jumps in Assembler, sometimes to go forward (if, switch), sometimes to go backward (for, while, do). But calling your own function is not logic. It´s not necessary to produce any outcome. Functionality is not enhanced by adding functions (subroutine calls) to your code. Nor is quality increased by adding functions. No performance gain, no higher scalability etc. through functions. Functions are not relevant to functionality. Strange, isn´t it. What they are important for is security of investment. By introducing functions into our code we can become more productive (re-use) and can increase evolvability (higher unterstandability, easier to keep code consistent). That´s no small feat, however. Evolvable code can hardly be overestimated. That´s why to me functional design is so important. It´s at the core of software development. To sum this up: Functional design is on a level of abstraction above (!) logical design or algorithmic design. Functional design is only done until you get to a point where each function is so simple you are very confident you can easily code it. Functional design an logical design (which mostly is coding, but can also be done using pseudo code or flow charts) are complementary. Software needs both. If you start coding right away you end up in a tangled mess very quickly. Then you need back out through refactoring. Functional design on the other hand is bloodless without actual code. It´s just a theory with no experiments to prove it. But how to do functional design? An example of functional design Let´s assume a program to de-duplicate strings. The user enters a number of strings separated by commas, e.g. a, b, a, c, d, b, e, c, a. And the program is supposed to clear this list of all doubles, e.g. a, b, c, d, e. There is only one Entry Point to this program: the user triggers the de-duplication by starting the program with the string list on the command line C:\>deduplicate "a, b, a, c, d, b, e, c, a" a, b, c, d, e …or by clicking on a GUI button. This leads to the Entry Point function to get called. It´s the program´s main function in case of the batch version or a button click event handler in the GUI version. That´s the physical Entry Point so to speak. It´s inevitable. What then happens is a three step process: Transform the input data from the user into a request. Call the request handler. Transform the output of the request handler into a tangible result for the user. Or to phrase it a bit more generally: Accept input. Transform input into output. Present output. This does not mean any of these steps requires a lot of effort. Maybe it´s just one line of code to accomplish it. Nevertheless it´s a distinct step in doing the processing behind an Entry Point. Call it an aspect or a responsibility - and you will realize it most likely deserves a function of its own to satisfy the Single Responsibility Principle (SRP). Interestingly the above list of steps is already functional design. There is no logic, but nevertheless the solution is described - albeit on a higher level of abstraction than you might have done yourself. But it´s still on a meta-level. The application to the domain at hand is easy, though: Accept string list from command line De-duplicate Present de-duplicated strings on standard output And this concrete list of processing steps can easily be transformed into code:static void Main(string[] args) { var input = Accept_string_list(args); var output = Deduplicate(input); Present_deduplicated_string_list(output); } Instead of a big problem there are three much smaller problems now. If you think each of those is trivial to implement, then go for it. You can stop the functional design at this point. But maybe, just maybe, you´re not so sure how to go about with the de-duplication for example. Then just implement what´s easy right now, e.g.private static string Accept_string_list(string[] args) { return args[0]; } private static void Present_deduplicated_string_list( string[] output) { var line = string.Join(", ", output); Console.WriteLine(line); } Accept_string_list() contains logic in the form of an API-call. Present_deduplicated_string_list() contains logic in the form of an expression and an API-call. And then repeat the functional design for the remaining processing step. What´s left is the domain logic: de-duplicating a list of strings. How should that be done? Without any logic at our disposal during functional design you´re left with just functions. So which functions could make up the de-duplication? Here´s a suggestion: De-duplicate Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Processing step 2 obviously was the core of the solution. That´s where real creativity was needed. That´s the core of the domain. But now after this refinement the implementation of each step is easy again:private static string[] Parse_string_list(string input) { return input.Split(',') .Select(s => s.Trim()) .ToArray(); } private static Dictionary<string,object> Compile_unique_strings(string[] strings) { return strings.Aggregate( new Dictionary<string, object>(), (agg, s) => { agg[s] = null; return agg; }); } private static string[] Serialize_unique_strings( Dictionary<string,object> dict) { return dict.Keys.ToArray(); } With these three additional functions Main() now looks like this:static void Main(string[] args) { var input = Accept_string_list(args); var strings = Parse_string_list(input); var dict = Compile_unique_strings(strings); var output = Serialize_unique_strings(dict); Present_deduplicated_string_list(output); } I think that´s very understandable code: just read it from top to bottom and you know how the solution to the problem works. It´s a mirror image of the initial design: Accept string list from command line Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Present de-duplicated strings on standard output You can even re-generate the design by just looking at the code. Code and functional design thus are always in sync - if you follow some simple rules. But about that later. And as a bonus: all the functions making up the process are small - which means easy to understand, too. So much for an initial concrete example. Now it´s time for some theory. Because there is method to this madness ;-) The above has only scratched the surface. Introducing Flow Design Functional design starts with a given function, the Entry Point. Its goal is to describe the behavior of the program when the Entry Point is triggered using a process, not an algorithm. An algorithm consists of logic, a process on the other hand consists just of steps or stages. Each processing step transforms input into output or a side effect. Also it might access resources, e.g. a printer, a database, or just memory. Processing steps thus can rely on state of some sort. This is different from Functional Programming, where functions are supposed to not be stateful and not cause side effects.[1] In its simplest form a process can be written as a bullet point list of steps, e.g. Get data from user Output result to user Transform data Parse data Map result for output Such a compilation of steps - possibly on different levels of abstraction - often is the first artifact of functional design. It can be generated by a team in an initial design brainstorming. Next comes ordering the steps. What should happen first, what next etc.? Get data from user Parse data Transform data Map result for output Output result to user That´s great for a start into functional design. It´s better than starting to code right away on a given function using TDD. Please get me right: TDD is a valuable practice. But it can be unnecessarily hard if the scope of a functionn is too large. But how do you know beforehand without investing some thinking? And how to do this thinking in a systematic fashion? My recommendation: For any given function you´re supposed to implement first do a functional design. Then, once you´re confident you know the processing steps - which are pretty small - refine and code them using TDD. You´ll see that´s much, much easier - and leads to cleaner code right away. For more information on this approach I call “Informed TDD” read my book of the same title. Thinking before coding is smart. And writing down the solution as a bunch of functions possibly is the simplest thing you can do, I´d say. It´s more according to the KISS (Keep It Simple, Stupid) principle than returning constants or other trivial stuff TDD development often is started with. So far so good. A simple ordered list of processing steps will do to start with functional design. As shown in the above example such steps can easily be translated into functions. Moving from design to coding thus is simple. However, such a list does not scale. Processing is not always that simple to be captured in a list. And then the list is just text. Again. Like code. That means the design is lacking visuality. Textual representations need more parsing by your brain than visual representations. Plus they are limited in their “dimensionality”: text just has one dimension, it´s sequential. Alternatives and parallelism are hard to encode in text. In addition the functional design using numbered lists lacks data. It´s not visible what´s the input, output, and state of the processing steps. That´s why functional design should be done using a lightweight visual notation. No tool is necessary to draw such designs. Use pen and paper; a flipchart, a whiteboard, or even a napkin is sufficient. Visualizing processes The building block of the functional design notation is a functional unit. I mostly draw it like this: Something is done, it´s clear what goes in, it´s clear what comes out, and it´s clear what the processing step requires in terms of state or hardware. Whenever input flows into a functional unit it gets processed and output is produced and/or a side effect occurs. Flowing data is the driver of something happening. That´s why I call this approach to functional design Flow Design. It´s about data flow instead of control flow. Control flow like in algorithms is of no concern to functional design. Thinking about control flow simply is too low level. Once you start with control flow you easily get bogged down by tons of details. That´s what you want to avoid during design. Design is supposed to be quick, broad brush, abstract. It should give overview. But what about all the details? As Robert C. Martin rightly said: “Programming is abot detail”. Detail is a matter of code. Once you start coding the processing steps you designed you can worry about all the detail you want. Functional design does not eliminate all the nitty gritty. It just postpones tackling them. To me that´s also an example of the SRP. Function design has the responsibility to come up with a solution to a problem posed by a single function (Entry Point). And later coding has the responsibility to implement the solution down to the last detail (i.e. statement, API-call). TDD unfortunately mixes both responsibilities. It´s just coding - and thereby trying to find detailed implementations (green phase) plus getting the design right (refactoring). To me that´s one reason why TDD has failed to deliver on its promise for many developers. Using functional units as building blocks of functional design processes can be depicted very easily. Here´s the initial process for the example problem: For each processing step draw a functional unit and label it. Choose a verb or an “action phrase” as a label, not a noun. Functional design is about activities, not state or structure. Then make the output of an upstream step the input of a downstream step. Finally think about the data that should flow between the functional units. Write the data above the arrows connecting the functional units in the direction of the data flow. Enclose the data description in brackets. That way you can clearly see if all flows have already been specified. Empty brackets mean “no data is flowing”, but nevertheless a signal is sent. A name like “list” or “strings” in brackets describes the data content. Use lower case labels for that purpose. A name starting with an upper case letter like “String” or “Customer” on the other hand signifies a data type. If you like, you also can combine descriptions with data types by separating them with a colon, e.g. (list:string) or (strings:string[]). But these are just suggestions from my practice with Flow Design. You can do it differently, if you like. Just be sure to be consistent. Flows wired-up in this manner I call one-dimensional (1D). Each functional unit just has one input and/or one output. A functional unit without an output is possible. It´s like a black hole sucking up input without producing any output. Instead it produces side effects. A functional unit without an input, though, does make much sense. When should it start to work? What´s the trigger? That´s why in the above process even the first processing step has an input. If you like, view such 1D-flows as pipelines. Data is flowing through them from left to right. But as you can see, it´s not always the same data. It get´s transformed along its passage: (args) becomes a (list) which is turned into (strings). The Principle of Mutual Oblivion A very characteristic trait of flows put together from function units is: no functional units knows another one. They are all completely independent of each other. Functional units don´t know where their input is coming from (or even when it´s gonna arrive). They just specify a range of values they can process. And they promise a certain behavior upon input arriving. Also they don´t know where their output is going. They just produce it in their own time independent of other functional units. That means at least conceptually all functional units work in parallel. Functional units don´t know their “deployment context”. They now nothing about the overall flow they are place in. They are just consuming input from some upstream, and producing output for some downstream. That makes functional units very easy to test. At least as long as they don´t depend on state or resources. I call this the Principle of Mutual Oblivion (PoMO). Functional units are oblivious of others as well as an overall context/purpose. They are just parts of a whole focused on a single responsibility. How the whole is built, how a larger goal is achieved, is of no concern to the single functional units. By building software in such a manner, functional design interestingly follows nature. Nature´s building blocks for organisms also follow the PoMO. The cells forming your body do not know each other. Take a nerve cell “controlling” a muscle cell for example:[2] The nerve cell does not know anything about muscle cells, let alone the specific muscel cell it is “attached to”. Likewise the muscle cell does not know anything about nerve cells, let a lone a specific nerve cell “attached to” it. Saying “the nerve cell is controlling the muscle cell” thus only makes sense when viewing both from the outside. “Control” is a concept of the whole, not of its parts. Control is created by wiring-up parts in a certain way. Both cells are mutually oblivious. Both just follow a contract. One produces Acetylcholine (ACh) as output, the other consumes ACh as input. Where the ACh is going, where it´s coming from neither cell cares about. Million years of evolution have led to this kind of division of labor. And million years of evolution have produced organism designs (DNA) which lead to the production of these different cell types (and many others) and also to their co-location. The result: the overall behavior of an organism. How and why this happened in nature is a mystery. For our software, though, it´s clear: functional and quality requirements needs to be fulfilled. So we as developers have to become “intelligent designers” of “software cells” which we put together to form a “software organism” which responds in satisfying ways to triggers from it´s environment. My bet is: If nature gets complex organisms working by following the PoMO, who are we to not apply this recipe for success to our much simpler “machines”? So my rule is: Wherever there is functionality to be delivered, because there is a clear Entry Point into software, design the functionality like nature would do it. Build it from mutually oblivious functional units. That´s what Flow Design is about. In that way it´s even universal, I´d say. Its notation can also be applied to biology: Never mind labeling the functional units with nouns. That´s ok in Flow Design. You´ll do that occassionally for functional units on a higher level of abstraction or when their purpose is close to hardware. Getting a cockroach to roam your bedroom takes 1,000,000 nerve cells (neurons). Getting the de-duplication program to do its job just takes 5 “software cells” (functional units). Both, though, follow the same basic principle. Translating functional units into code Moving from functional design to code is no rocket science. In fact it´s straightforward. There are two simple rules: Translate an input port to a function. Translate an output port either to a return statement in that function or to a function pointer visible to that function. The simplest translation of a functional unit is a function. That´s what you saw in the above example. Functions are mutually oblivious. That why Functional Programming likes them so much. It makes them composable. Which is the reason, nature works according to the PoMO. Let´s be clear about one thing: There is no dependency injection in nature. For all of an organism´s complexity no DI container is used. Behavior is the result of smooth cooperation between mutually oblivious building blocks. Functions will often be the adequate translation for the functional units in your designs. But not always. Take for example the case, where a processing step should not always produce an output. Maybe the purpose is to filter input. Here the functional unit consumes words and produces words. But it does not pass along every word flowing in. Some words are swallowed. Think of a spell checker. It probably should not check acronyms for correctness. There are too many of them. Or words with no more than two letters. Such words are called “stop words”. In the above picture the optionality of the output is signified by the astrisk outside the brackets. It means: Any number of (word) data items can flow from the functional unit for each input data item. It might be none or one or even more. This I call a stream of data. Such behavior cannot be translated into a function where output is generated with return. Because a function always needs to return a value. So the output port is translated into a function pointer or continuation which gets passed to the subroutine when called:[3]void filter_stop_words( string word, Action<string> onNoStopWord) { if (...check if not a stop word...) onNoStopWord(word); } If you want to be nitpicky you might call such a function pointer parameter an injection. And technically you´re right. Conceptually, though, it´s not an injection. Because the subroutine is not functionally dependent on the continuation. Firstly continuations are procedures, i.e. subroutines without a return type. Remember: Flow Design is about unidirectional data flow. Secondly the name of the formal parameter is chosen in a way as to not assume anything about downstream processing steps. onNoStopWord describes a situation (or event) within the functional unit only. Translating output ports into function pointers helps keeping functional units mutually oblivious in cases where output is optional or produced asynchronically. Either pass the function pointer to the function upon call. Or make it global by putting it on the encompassing class. Then it´s called an event. In C# that´s even an explicit feature.class Filter { public void filter_stop_words( string word) { if (...check if not a stop word...) onNoStopWord(word); } public event Action<string> onNoStopWord; } When to use a continuation and when to use an event dependens on how a functional unit is used in flows and how it´s packed together with others into classes. You´ll see examples further down the Flow Design road. Another example of 1D functional design Let´s see Flow Design once more in action using the visual notation. How about the famous word wrap kata? Robert C. Martin has posted a much cited solution including an extensive reasoning behind his TDD approach. So maybe you want to compare it to Flow Design. The function signature given is:string WordWrap(string text, int maxLineLength) {...} That´s not an Entry Point since we don´t see an application with an environment and users. Nevertheless it´s a function which is supposed to provide a certain functionality. The text passed in has to be reformatted. The input is a single line of arbitrary length consisting of words separated by spaces. The output should consist of one or more lines of a maximum length specified. If a word is longer than a the maximum line length it can be split in multiple parts each fitting in a line. Flow Design Let´s start by brainstorming the process to accomplish the feat of reformatting the text. What´s needed? Words need to be assembled into lines Words need to be extracted from the input text The resulting lines need to be assembled into the output text Words too long to fit in a line need to be split Does sound about right? I guess so. And it shows a kind of priority. Long words are a special case. So maybe there is a hint for an incremental design here. First let´s tackle “average words” (words not longer than a line). Here´s the Flow Design for this increment: The the first three bullet points turned into functional units with explicit data added. As the signature requires a text is transformed into another text. See the input of the first functional unit and the output of the last functional unit. In between no text flows, but words and lines. That´s good to see because thereby the domain is clearly represented in the design. The requirements are talking about words and lines and here they are. But note the asterisk! It´s not outside the brackets but inside. That means it´s not a stream of words or lines, but lists or sequences. For each text a sequence of words is output. For each sequence of words a sequence of lines is produced. The asterisk is used to abstract from the concrete implementation. Like with streams. Whether the list of words gets implemented as an array or an IEnumerable is not important during design. It´s an implementation detail. Does any processing step require further refinement? I don´t think so. They all look pretty “atomic” to me. And if not… I can always backtrack and refine a process step using functional design later once I´ve gained more insight into a sub-problem. Implementation The implementation is straightforward as you can imagine. The processing steps can all be translated into functions. Each can be tested easily and separately. Each has a focused responsibility. And the process flow becomes just a sequence of function calls: Easy to understand. It clearly states how word wrapping works - on a high level of abstraction. And it´s easy to evolve as you´ll see. Flow Design - Increment 2 So far only texts consisting of “average words” are wrapped correctly. Words not fitting in a line will result in lines too long. Wrapping long words is a feature of the requested functionality. Whether it´s there or not makes a difference to the user. To quickly get feedback I decided to first implement a solution without this feature. But now it´s time to add it to deliver the full scope. Fortunately Flow Design automatically leads to code following the Open Closed Principle (OCP). It´s easy to extend it - instead of changing well tested code. How´s that possible? Flow Design allows for extension of functionality by inserting functional units into the flow. That way existing functional units need not be changed. The data flow arrow between functional units is a natural extension point. No need to resort to the Strategy Pattern. No need to think ahead where extions might need to be made in the future. I just “phase in” the remaining processing step: Since neither Extract words nor Reformat know of their environment neither needs to be touched due to the “detour”. The new processing step accepts the output of the existing upstream step and produces data compatible with the existing downstream step. Implementation - Increment 2 A trivial implementation checking the assumption if this works does not do anything to split long words. The input is just passed on: Note how clean WordWrap() stays. The solution is easy to understand. A developer looking at this code sometime in the future, when a new feature needs to be build in, quickly sees how long words are dealt with. Compare this to Robert C. Martin´s solution:[4] How does this solution handle long words? Long words are not even part of the domain language present in the code. At least I need considerable time to understand the approach. Admittedly the Flow Design solution with the full implementation of long word splitting is longer than Robert C. Martin´s. At least it seems. Because his solution does not cover all the “word wrap situations” the Flow Design solution handles. Some lines would need to be added to be on par, I guess. But even then… Is a difference in LOC that important as long as it´s in the same ball park? I value understandability and openness for extension higher than saving on the last line of code. Simplicity is not just less code, it´s also clarity in design. But don´t take my word for it. Try Flow Design on larger problems and compare for yourself. What´s the easier, more straightforward way to clean code? And keep in mind: You ain´t seen all yet ;-) There´s more to Flow Design than described in this chapter. In closing I hope I was able to give you a impression of functional design that makes you hungry for more. To me it´s an inevitable step in software development. Jumping from requirements to code does not scale. And it leads to dirty code all to quickly. Some thought should be invested first. Where there is a clear Entry Point visible, it´s functionality should be designed using data flows. Because with data flows abstraction is possible. For more background on why that´s necessary read my blog article here. For now let me point out to you - if you haven´t already noticed - that Flow Design is a general purpose declarative language. It´s “programming by intention” (Shalloway et al.). Just write down how you think the solution should work on a high level of abstraction. This breaks down a large problem in smaller problems. And by following the PoMO the solutions to those smaller problems are independent of each other. So they are easy to test. Or you could even think about getting them implemented in parallel by different team members. Flow Design not only increases evolvability, but also helps becoming more productive. All team members can participate in functional design. This goes beyon collective code ownership. We´re talking collective design/architecture ownership. Because with Flow Design there is a common visual language to talk about functional design - which is the foundation for all other design activities.   PS: If you like what you read, consider getting my ebook “The Incremental Architekt´s Napkin”. It´s where I compile all the articles in this series for easier reading. I like the strictness of Function Programming - but I also find it quite hard to live by. And it certainly is not what millions of programmers are used to. Also to me it seems, the real world is full of state and side effects. So why give them such a bad image? That´s why functional design takes a more pragmatic approach. State and side effects are ok for processing steps - but be sure to follow the SRP. Don´t put too much of it into a single processing step. ? Image taken from www.physioweb.org ? My code samples are written in C#. C# sports typed function pointers called delegates. Action is such a function pointer type matching functions with signature void someName(T t). Other languages provide similar ways to work with functions as first class citizens - even Java now in version 8. I trust you find a way to map this detail of my translation to your favorite programming language. I know it works for Java, C++, Ruby, JavaScript, Python, Go. And if you´re using a Functional Programming language it´s of course a no brainer. ? Taken from his blog post “The Craftsman 62, The Dark Path”. ?

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  • SQLAuthority News – Book Signing Event – SQLPASS 2011 Event Log

    - by pinaldave
    I have been dreaming of writing book for really long time, and I finally got the chance – in fact, two chances!  I recently wrote two books: SQL Programming Joes 2 Pros: Programming and Development for Microsoft SQL Server 2008 [Amazon] | [Flipkart] | [Kindle] and SQL Wait Stats Joes 2 Pros: SQL Performance Tuning Techniques Using Wait Statistics, Types & Queues [Amazon] | [Flipkart] | [Kindle].  I had a lot of fun writing these two books, even though sometimes I had to sacrifice some family time and time for other personal development to write the books. The good side of writing book is that when the efforts put in writing books are recognize by books readers and kind organizations like expressor studio. Book Signing Event Book writing is a complex process.  Even after you spend months, maybe years, writing the material you still have to go through the editing and fact checking processes.  And, once the book is out there, there is no way to take back all the copies to change mistakes or add something you forgot.  Most of the time it is a one-way street. Book Signing Event Just like every author, I had a dream that after the books were written, they would be loved by people and gain acceptance by an audience. My first book, SQL Programming Joes 2 Pros: Programming and Development for Microsoft SQL Server 2008, is extremely popular because it helps lots of people learn various fundamental topics. My second book covers beginning to learn SQL Server Wait Stats, which is a relatively new subject. This book has had very good acceptance in the community. Book Signing Event Helping my community is my primary focus, so I was happy to see this year’s SQLPASS tag line: ‘This is a Community.‘ At the event, the expressor studio guys came up with a very novel idea. They had previously used my books and they had found them very useful. They got 100 copies of the book and decided to give it away to community folks. They invited me and my co-author Rick Morelan to hold a book signing event. We did a book signing on Thursday between 1 pm and 2 pm. Book Signing Event This event was one of the best events for me. This was my first book signing event outside of India. I reached the book signing location around 20 minutes before the scheduled time and what I saw was a big line for the book signing event. I felt very honored looking at the crowd and all the people around the event location. I felt very humbled when I saw some of my very close friends standing in the line to get my signature. It was really heartwarming to see so many enthusiasts waiting for more than an hour to get my signature. While standing in line I had the chance to have a conversation with every single person who showed up for the signature. I made sure that I repeated every single name and wrote it in every book with my signature. There is saying that if we write a name once we will remember it forever. I want to remember all of you who saw me at the book signing. Your comments were wonderful, your feedback was amazing and you were all very supportive. Book Signing Event I have made a note of every conversation I had with all of you when I was signing the books. Once again, I just want to express my thanks for coming to my book signing event. The whole experience was very humbling. On the top of it, I want to thank the expressor studio people who made it possible, who organized the whole signing event. I am so thankful to them for facilitating the whole experience, which is going to be hard to beat by any future experience. My books Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL PASS, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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  • F# in ASP.NET, mathematics and testing

    - by DigiMortal
    Starting from Visual Studio 2010 F# is full member of .NET Framework languages family. It is functional language with syntax specific to functional languages but I think it is time for us also notice and study functional languages. In this posting I will show you some examples about cool things other people have done using F#. F# and ASP.NET As I am ASP/ASP.NET MVP I am – of course – interested in how people use different languages and technologies with ASP.NET. C# MVP Tomáš Petrícek writes about developing ASP.NET MVC applications using F#. He also shows how to use LINQ To SQL in F# (using F# PowerPack) and provides sample solution and Visual Studio 2010 template for F# MVC web applications. You may also find interesting how you can create controllers in F#. Excellent work, Tomáš! Vladimir Matveev has interesting example about how to use F# and ApplicationHost class to process ASP.NET requests ouside of IIS. This is simple and very straight-forward example and I strongly suggest you to take a look at it. Very cool example is project Strom in Codeplex. Storm is web services testing tool that is fully written on F#. Take a look at this site because Codeplex offers also source code besides binaries. Math Functional languages are strong in fields like mathematics and physics. When I wrote my C# example about BigInteger class I found out that recursive version of Fibonacci algorithm in C# is not performing well. In same time I made same experiment on F# and in F# there were no performance problems with recursive version. You can find F# version of Fibonacci algorithm from Bob Palmer’s blog posting Fibonacci numbers in F#. Although golden spiral is useful for solving many problems I looked for some practical code example and found one. Kean Walmsley published in his Through the Interface blog very interesting posting Creating Fibonacci spirals in AutoCAD using F#. There are also other cool examples you may be interested in. Using numerical components by Extreme Optimization  it is possible to make some numerical integration (quadrature method) using F# (also C# example is available). fsharp.it introduces factorials calculation on F#. Robert Pickering has made very good work on programming The Game of Life in Silverlight and F# – I definitely suggest you to try out this example as it is very illustrative too. Who wants something more complex may take a look at Newton basin fractal example in F# by Jonathan Birge. Testing After some searching and surfing I found out that there is almost everything available for F# to write tests and test your F# code. FsCheck - FsCheck is a port of Haskell's QuickCheck. Important parts of the manual for using FsCheck is almost literally "adapted" from the QuickCheck manual and paper. Any errors and omissions are entirely my responsibility. FsTest - This project is designed to Language Oriented Programming constructs around unit testing and behavior testing in F#. The goal of this project is to create a Domain Specific Language for testing F# code in a way that makes sense for functional programming. FsUnit - FsUnit makes unit-testing with F# more enjoyable. It adds a special syntax to your favorite .NET testing framework. xUnit.NET - xUnit.net is a developer testing framework, built to support Test Driven Development, with a design goal of extreme simplicity and alignment with framework features. It is compatible with .NET Framework 2.0 and later, and offers several runners: console, GUI, MSBuild, and Visual Studio integration via TestDriven.net, CodeRush Test Runner and Resharper. It also offers test project integration for ASP.NET MVC. Getting started Well, as a first thing you need Visual Studio 2010. Then take a look at these resources: F# samples @ MSDN Microsoft F# Developer Center @ MSDN F# Language Reference @ MSDN F# blog F# forums Real World Functional Programming: With Examples in F# and C# (Amazon) Happy F#-ing! :)

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  • Thoughts on Thoughts on TDD

    Brian Harry wrote a post entitled Thoughts on TDD that I thought I was going to let lie, but I find that I need to write a response. I find myself in agreement with Brian on many points in the post, but I disagree with his conclusion. Not surprisingly, I agree with the things that he likes about TDD. Focusing on the usage rather than the implementation is really important, and this is important whether you use TDD or not. And YAGNI was a big theme in my Seven Deadly Sins of Programming series. Now, on to what he doesnt like. He says that he finds it inefficient to have tests that he has to change every time he refactors. Here is where we part company. If you are having to do a lot of test rewriting (say, more than a couple of minutes work to get back to green) *often* when you are refactoring your code, I submit that either you are testing things that you dont need to test (internal details rather than external implementation), your code perhaps isnt as decoupled as it could be, or maybe you need a visit to refactorers anonymous. I also like to refactor like crazy, but as we all know, the huge downside of refactoring is that we often break things. Important things. Subtle things. Which makes refactoring risky. *Unless* we have a set of tests that have great coverage. And TDD (or Example-based Design, which I prefer as a term) gives those to us. Now, I dont know what sort of coverage Brian gets with the unit tests that he writes, but I do know that for the majority of the developers Ive worked with and I count myself in that bucket the coverage of unit tests written afterwards is considerably inferior to the coverage of unit tests that come from TDD. For me, it all comes down to the answer to the following question: How do you ensure that your code works now and will continue to work in the future? Im willing to put up with a little efficiency on the front side to get that benefit later. Its not the writing of the code thats the expensive part, its everything else that comes after. I dont think that stepping through test cases in the debugger gets you what you want. You can verify what the current behavior is, sure, and do it fairly cheaply, but you dont help the guy in the future who doesnt know what conditions were important if he has to change your code. His second part that he doesnt like backing into an architecture (go read to see what he means). Ive certainly had to work with code that was like this before, and its a nightmare the code that nobody wants to touch. But thats not at all the kind of code that you get with TDD, because if youre doing it right youre doing the write a failing tests, make it pass, refactor approach. Now, you may miss some useful refactorings and generalizations for this, but if you do, you can refactor later because you have the tests that make it safe to do so, and your code tends to be easy to refactor because the same things that make code easy to write unit tests for make it easy to refactor. I also think Brian is missing an important point. We arent all as smart as he is. Im reminded a bit of the lesson of Intentional Programming, Charles Simonyis paradigm for making programming easier. I played around with Intentional Programming when it was young, and came to the conclusion that it was a pretty good thing if you were as smart as Simonyi is, but it was pretty much a disaster if you were an average developer. In this case, TDD gives you a way to work your way into a good, flexible, and functional architecture when you dont have somebody of Brians talents to help you out. And thats a good thing.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • A .NET Developers day with the iPad.

    - by mbcrump
    The Apple iPad is currently getting a lot of buzz because of the app store, the book store and of course iTunes. I had the chance to play with one and this is what I have learned about the device. Let’s get this out of the way first, the iPad is awesome. It is the device for media consumption and casual web browsing. But how does it measure up to those of us with .NET on our brains all days. Let’s find out… Main Screen – you can customize everything on this page. I guess I should replace that image with a C# or VS logo. Its pretty standard stuff if you have an iPhone.   Programming Books If you have a subscription to Safari Books Online, then you are in luck, its very easy to read the books on the iPad. Just fire up Safari web browser and goto the Safari Books Online. The biggest benefit that I can see with the iPad is the ability to read books wherever and not have to worry about purchasing books that I already have the .PDF for. Below is a sample from Code Complete 2nd Edition. Below is a PDF of the ECMA-334 C# Language Specification. As you can see its very readable and you should have no problem reading actual code.   Example of Code shown below: It is however easier to read the PDF and store them with a 3rd party PDF reader. I have seen several for .99 cents or less. You can however switch the screen to vertical to get more viewing space as shown below: I was disappointed with the iBooks application. I could not find a single .NET programming book anywhere. I was able to download the excellent sci-fi book “A memory of Wind” for free though. If I just overlooked them, then please email me with the names and titles. I couldn’t even find a technology category in the categories list. Web Surfing – Technical Sites Below is an example of my site in Safari. The code is very readable and the experience was identical to viewing it in Firefox. I tried multiple programming site and the pages looked great except those that used flash and of course it did not display on those pages.   News Apps - Technical Content The standard NY Times and USA Today looked great, but the Technical Content was lacking. It would probably be better to use Google Reader for online technical news.     YouTube Videos – Technical Content  Since its YouTube, we already know that a lot of technical content exist and it plays great on the iPad. I watched several programming videos and could clearly see the code being written. Taking Technical Notes The iPad comes with a great notepad for taking notes. I found that it was easy to take notes regarding projects that I am currently working on.   Calendar The calendar that ships with the iPad is great for organizing. You can setup exchange server or manually enter the information. Pretty standard stuff.    Random Applications that I like: TweetDeck.   and Adobe Ideas. Adobe Ideas is kinda like SketchFlow except you use your finger to mock up the sketches.  Don’t forget that the iPad is great for any type of podcasting. That pretty much sums it up, I would definitely recommend this device as it will only get better. I believe the iOS4 comes out on the 24th and the iPad will only get more and more apps. You could save a few bucks by waiting for the 2nd generation, but that’s a call that only you can make.

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  • Applying for internship

    - by Margus
    At the moment I'm thinking about applying for internship at Eesti Energia. I seem to be eligible, but before contacting them I need to learn how to compile an informative and complete CV and cover letter. I do not consider myself as shallow minded, but also I'm not sure how to convincingly justify the stand of interest and how internship will help me in my future career. Course of life Tallinna Tehnikagümnaasium 2003 - 2006 Tallinna Tehnikaülikool 2006 – 2009 Military service at Signal Batallion Tallinna Tehnikaülikool 2010 – ... I started my academic career as Computer and Systems Engineer, but as I excelled in programming classes, I changed my major to Software Engineer and taken my specialty in web applications and logic. Nowadays I mainly use Java, Mathematica and C# to solve problems. For 2 times, I have taken part in ACM International Collegiate Programming Contest, where my team won the nationals and did pretty well in Europe. Also as part of notable thing in my academic career, my team wrote the Kalah game AI, that won in University's main programming class AI tournament. My hobbies are mind games and occasional problem solving. Few years ago I also competed in International Checkers EM (requires being in top 3 in nationals) as part of cadet and junior age group - I did not come close to winning, but I exceeded about half of the players each time. In high school and gymnasium I took part and later was the captain of team, that passes regionals and made it to top 3 of nationals (and later won) in (blitz) russian checkers. That was impressive because, it was a team effort as we only had (depending on year) 2-3 strong players. Although I started programming exactly 9,5 years ago I have no work experience. Well actually thats not true, as I completed my army duty, I was hired for a year (days still counting) to be apart of communicational (emergency) infrastructure action group where I'm the teams IT specialist (it's more complicated). So I consider myself to be aware of: rough conditions, teamwork, high stress tolerance, being on time and what responsibility means. As negative things I can mention: I do not have drivers licence. Although only Estonian and English are noted as requirements, then Russian is most likely required as well and I barely understand some of it. Reasons why I want to apply there, are: I need to do at least 4-6 week traineeship and it's in the right field I have the requirements and tasks seem easy enough Company is well known and has fairly good reputation Family and friend think, that it would be acceptable place to work Myriad of options to do final thesis about open up Work place is located in the same city I live atm. At moment, I see myself having a hard time explain why I would prefer it or where I see myself in 10 years if I was offered a job there. Question I have some idea how Curriculum Vitæ should look like, or I can google for template, but I'm not sure how to write informative one. Last I did one, it looked like: picture + contact information + education. Vaguely I only remember, that cover letter should be custom tailored for each place you apply containing ...

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  • I am not satisfied with my career and accomplished nothing in my life. what should I do now [on hold]

    - by user2906155
    After my complete my College education I got chance to work on software programming. I work on few software and now nothing make me feel good. I don't like web-programming. Can't have too much mind to play with other people in team a designer or a senior. it's totally time wasting for me. We do integration without any source code control. copy through pen drive. I write in too many language for web-programming but know nothing about any language specially. I don't like to have a BOSS. I would like to do something on my own. From last 3 year I thing I will got a better job but I am unable to get it. I am not good at Programming nor my English is native. I have a big list for pay then my salary. I have problem with nothing. my atmosphere is about illiterate people. they abuse 24 hours a day. this thing make me sick. people watch CRIME patrol my home (watching rape in TV because it's happen to someone). I do my work from home. I don't like to live in my state. All state is one of the biggest illiterate state of my country. Once I apply for a Job in China and it's look like I can get thing Job but I don't get it. My family doesn't want me to settle anywhere else. I told my family 4 time a day that I can't live in this worst situation. Everyone (including the person who I work for) tell me that you can do it only you have money. Now I really don't know how to make money. My job not allow me to work for anyone. My productivity going down since I don't learn anything new. I thing if this happen to me for next 2 year I don't have any knowledge more then a peon. I hate it. When I was in other city then I see that if I spent 7 days their all my 7 days going better. even I go for travelling in green places then I like it. but all I hate it where I work for. When I work on other city then I see my productivity are improved and I don't hate my work. I listen a song "If you don't your love what are you doing it for". I seriously don' t know what I still live here because this place gave me nothing but depression and trouble. for people I clear that I don't belong to RICH or middle class family. All I got is doing something on my own or help of someone. affording a rental place make my run on footpath. All I save in one month is just 10$ (approximately) (actually I afford some guys's education now). Can a programmer live worst life like this. I really not happy. Today is a festival in India and I don't celebrate it because I really hate myself. I want to do suicide. someone guide me how to start solving this headache

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  • A programmer who doesn't get to program - where to turn? [closed]

    - by Just an Anon
    I'm in my mid 20's, and have been working as a full time programmer / developer for the last ~6 years, with several years of part-time freelancing before this, and three straight years of freelancing in the middle of this short career. I work mostly with PHP and the Drupal framework. By and large, I focus on programming custom pieces of functionality; these, of course, vary greatly from project to project. I've got years of solid experience with OOP (have done some Java & C# years ago, too) including intensive experience with front-end development, and even some design work. I've lead small teams (2-4 people) of developers. And of course, given the large amount of freelancing, I've got decent project- & client-management skills. My problem is staying motivated at any place of employment. In the time mentioned I've worked (full-time) at six local companies. The longest I've stayed at any company was just over a year. I find that I'll get hired and be very excited and motivated for the first few months, but the work quickly gets "stale." By that I mean that the interesting components (ie. the programming) get done, and the rest of the work turns into boring cleanup (move a button, add text, change colours, add a field). I don't get challenged, and I don't feel like I'm learning anything new. This happens repeatedly time and time again, and I always end up leaving for either a new opportunity, or to freelance. I'm wondering if perhaps I've painted myself into a corner with the rather niche work market (although with very high demand and good compensation) and need to explore other career choices. Another possibility is that I may be choosing the wrong places of employment, mostly small agencies, and need to look into working for a larger, more established firm. I find programming, writing code, and architecting solutions very rewarding. When I'm working on an interesting problem I lose all sense of time and 14-16 hours can fly by like minutes. I get the same exciting feeling when I'm doing high-level planning of a complex system, breaking up the work and figuring out how everything will tie-in together. I absolutely hate doing small, "stupid" changes that pose no challenge, yet seem to make up more and more of my work. I want to find a workplace where I will get to work on such tasks, be challenged, and improve in all areas of product development. This maybe a programming job, management, architecture of desktop apps, or may be managing a taco stand on a beach in Mexico - I don't know, and I need some advice and real-world feedback. What are some job areas worth exploring? The requirements are fairly simple: working with computers interacting with others challenging decent pay (I'm making just short of 90k / year with a month of vacation & some benefits, and would like to stay in this range, but am willing to take a temporary cut in pay for a more interesting position) Any advice would be much appreciated!

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  • Why is 0 false?

    - by Morwenn
    This question may sound dumb, but why does 0 evaluates to false and any other [integer] value to true is most of programming languages? String comparison Since the question seems a little bit too simple, I will explain myself a little bit more: first of all, it may seem evident to any programmer, but why wouldn't there be a programming language - there may actually be, but not any I used - where 0 evaluates to true and all the other [integer] values to false? That one remark may seem random, but I have a few examples where it may have been a good idea. First of all, let's take the example of strings three-way comparison, I will take C's strcmp as example: any programmer trying C as his first language may be tempted to write the following code: if (strcmp(str1, str2)) { // Do something... } Since strcmp returns 0 which evaluates to false when the strings are equal, what the beginning programmer tried to do fails miserably and he generally does not understand why at first. Had 0 evaluated to true instead, this function could have been used in its most simple expression - the one above - when comparing for equality, and the proper checks for -1 and 1 would have been done only when needed. We would have considered the return type as bool (in our minds I mean) most of the time. Moreover, let's introduce a new type, sign, that just takes values -1, 0 and 1. That can be pretty handy. Imagine there is a spaceship operator in C++ and we want it for std::string (well, there already is the compare function, but spaceship operator is more fun). The declaration would currently be the following one: sign operator<=>(const std::string& lhs, const std::string& rhs); Had 0 been evaluated to true, the spaceship operator wouldn't even exist, and we could have declared operator== that way: sign operator==(const std::string& lhs, const std::string& rhs); This operator== would have handled three-way comparison at once, and could still be used to perform the following check while still being able to check which string is lexicographically superior to the other when needed: if (str1 == str2) { // Do something... } Old errors handling We now have exceptions, so this part only applies to the old languages where no such thing exist (C for example). If we look at C's standard library (and POSIX one too), we can see for sure that maaaaany functions return 0 when successful and any integer otherwise. I have sadly seen some people do this kind of things: #define TRUE 0 // ... if (some_function() == TRUE) { // Here, TRUE would mean success... // Do something } If we think about how we think in programming, we often have the following reasoning pattern: Do something Did it work? Yes -> That's ok, one case to handle No -> Why? Many cases to handle If we think about it again, it would have made sense to put the only neutral value, 0, to yes (and that's how C's functions work), while all the other values can be there to solve the many cases of the no. However, in all the programming languages I know (except maybe some experimental esotheric languages), that yes evaluates to false in an if condition, while all the no cases evaluate to true. There are many situations when "it works" represents one case while "it does not work" represents many probable causes. If we think about it that way, having 0 evaluate to true and the rest to false would have made much more sense. Conclusion My conclusion is essentially my original question: why did we design languages where 0 is false and the other values are true, taking in account my few examples above and maybe some more I did not think of? Follow-up: It's nice to see there are many answers with many ideas and as many possible reasons for it to be like that. I love how passionate you seem to be about it. I originaly asked this question out of boredom, but since you seem so passionate, I decided to go a little further and ask about the rationale behind the Boolean choice for 0 and 1 on Math.SE :)

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