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  • 'Photo editor' and 'RAW editor' in Shotwell

    - by Chris Wilson
    The preference menu in Shotwell allows the user to specify both an 'External photo editor' and an 'External RAW editor', but I'm confused as to why two external editors would be required. I'm not a photographer, so this confusion may simply be a result of my ignorance, but I thought RAW images were unprocessed photographs, in which case two editors would be kinda redundant. Am I simply missing one of the finer details of photograph processing?

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  • Load balancing and HTTPS strategies

    - by Dan
    I am faced with the following problem: Servers get saturated since current load balancing strategy is based on client IP. Some corporate clients access our servers from behind large proxies so all clients appear with same IP to our load balancer. I think we are using some hardware load balancing device (can investigate further if necessary). We need to maintain session affinity (site is constructed in ASP), so all requests with same IP get routed to the same node. Since all the communication goes over the HTTPS, no request data (like session Id) is available to balancer as a client discriminator. Is there a way to use some other data besides the IP to distinguish between clients and route the clients even when coming from same IP to different nodes? Note: I need to maintain the traffic between the balancer and nodes safe (encrypted).

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  • Using DNS in iproute2

    - by Oliver
    In my setup I can redirect the default gateway based on the source address. Let's say a user is connected through tun0 (10.2.0.0/16) is redirect to another vpn. That works fine! ip rule add from 10.2.0.10 lookup vpn1 In a second rule I redirect the default gateway to another gateway if the user access a certain ip adress: ip rule add from 10.2.0.10 to 94.142.154.71 lookup vpn2 If I access the page on 94.142.154.71 (myip.is) the user is correctly routed and I can see the ip of the second vpn. On any other pages the ip address of vpn1 is shown. But how do I tell iproute2 that all request at e. g. google.com should be redirected through vpn2?

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  • how to point godaddy to my entrydns domain

    - by geminiCoder
    I have a server connected via dynamic ip. I have set up entrydns to manage the change of my ip. If I put in my entrydns url it points me to my servers current ip. I purchased a domain from go daddy, but I have been unable to get it to point to my entrydns. What I want is to be able to ssh to my server. but ideally id like to do this by using my domain name. I must confess Im a bit overwhelmed by the godaddy interface. So The bottom line is how do I point my godaddy domain to my dns domain so that when I look up the domain I get the current ip of the server?

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  • Getting to grips with the stack in nasm

    - by MarkPearl
    Today I spent a good part of my day getting to grips with the stack and nasm. After looking at my notes on nasm I think this is one area for the course I am doing they could focus more on… So here are some snippets I have put together that have helped me understand a little bit about the stack… Simplest example of the stack You will probably see examples like the following in circulation… these demonstrate the simplest use of the stack… org 0x100 bits 16 jmp main main: push 42h push 43h push 44h mov ah,2h ;set to display characters pop dx    ;get the first value int 21h   ;and display it pop dx    ;get 2nd value int 21h   ;and display it pop dx    ;get 3rd value int 21h   ;and display it int 20h The output from above code would be… DCB Decoupling code using “call” and “ret” This is great, but it oversimplifies what I want to use the stack for… I do not know if this goes against the grain of assembly programmers or not, but I want to write loosely coupled assembly code – and I want to use the stack as a mechanism for passing values into my decoupled code. In nasm we have the call and return instructions, which provides a mechanism for decoupling code, for example the following could be done… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov ah,2h mov dx,41h int 21h ret ;---------------------------------------- main: call displayChar int 20h   This would output the following to the console A So, it would seem that call and ret allow us to jump to segments of our code and then return back to the calling position – a form of segmenting the code into what we would called in higher order languages “functions” or “methods”. The only issue is, in higher order languages there is a way to pass parameters into the functions and return results. Because of the primitive nature of the call and ret instructions, this does not seem to be obvious. We could of course use the registers to pass values into the subroutine and set values coming out, but the problem with this is we… Have a limited number of registers Are threading our code with tight coupling (it would be hard to migrate methods outside of their intended use in a particular program to another one) With that in mind, I turn to the stack to provide a loosely coupled way of calling subroutines… First attempt with the Stack Initially I thought this would be simple… we could use code that looks as follows to achieve what I want… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov ah,2h pop dx int 21h ret ;---------------------------------------- main: push 41h call displayChar int 20h   However running this application does not give the desired result, I want an ‘A’ to be returned, and I am getting something totally different (you will to). Reading up on the call and ret instructions a discovery is made… they are pushing and popping things onto and off the stack as well… When the call instruction is executed, the current value of IP (the address of the instruction to follow) is pushed onto the stack, when ret is called, the last value on the stack is popped off into the IP register. In effect what the above code is doing is as follows with the stack… push 41h push current value of ip pop current value of ip to dx pop 41h to ip This is not what I want, I need to access the 41h that I pushed onto the stack, but the call value (which is necessary) is putting something in my way. So, what to do? Remember we have other registers we can use as well as a thing called indirect addressing… So, after some reading around, I came up with the following approach using indirect addressing… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov bp,sp mov ah,2h mov dx,[bp+2] int 21h ret ;---------------------------------------- main: push 41h call displayChar int 20h In essence, what I have done here is used a trick with the stack pointer… it goes as follows… Push 41 onto the stack Make the call to the function, which will push the IP register onto the stack and then jump to the displayChar label Move the value in the stack point to the bp register (sp currently points at IP register) Move the at the location of bp minus 2 bytes to dx (this is now the value 41h) display it, execute the ret instruction, which pops the ip value off the stack and goes back to the calling point This approach is still very raw, some further reading around shows that I should be pushing the value of bp onto the stack before replacing it with sp, but it is the starting thread to getting loosely coupled subroutines. Let’s see if you get what the following output would be? org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov bp,sp mov ah,2h mov dx,[bp+4] int 21h mov dx,[bp+2] int 21h ret ;---------------------------------------- main: push 41h push 42h call displayChar int 20h The output is… AB Where to from here? If by any luck some assembly programmer comes along and see this code and notices that I have made some fundamental flaw in my logic… I would like to know, so please leave a comment… appreciate any feedback!

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  • Email sent from server with rDNS & SPF being blocked by Hotmail

    - by Canadaka
    I have been unable to send email to users on hotmail or other Microsoft email servers for some time. Its been a major headache trying to find out why and how to fix the issue. The emails being sent that are blocked from my domain canadaka.net. I use Google Aps to host my regular email serverice for my @canadaka.net email addresses. I can sent email from my desktop or gmail to a hotmail without any problem. But any email sent from my server on behalf of canadaka.net is blocked, not even arriving in the junk email. The IP that the emails are being sent from is the same IP that my site is hosted on: 66.199.162.177 This IP is new to me since August 2010, I had a different IP for the previous 3-4 years. This IP is not on any credible spam lists http://www.anti-abuse.org/multi-rbl-check-results/?host=66.199.162.177 The one list spamcannibal.org my IP is listed on seems to be out of my control, says "no reverse DNS, MX host should have rDNS - RFC1912 2.1". But since I use Google for my email hosting, I don't have control over setting up RDNS for all the MX records. I do have Reverse DNS setup for my IP though, it resolves to "mail.canadaka.net". I have signed up for SNDS and was approved. My ip says "All of the specified IPs have normal status." Sender Score: 100 https://www.senderscore.org/lookup.php?lookup=66.199.162.177&ipLookup.x=55&ipLookup.y=14 My Mcafee threat level seems fine I have a TXT SPF record setup, I am currently using xname.org as my DNS, and they don't have a field for SPF, but their FAQ says to add the SPF info as a TXT entry. v=spf1 a include:_spf.google.com ~all Some "SPF checking" tools ive used detect that my domain has a valid SPF, but others don't. Like Microsoft's SPF wizard, i think this is because its specifically looking for an SPF record and not in the TXT. "No SPF Record Found. A and MX Records Available". From my home I can run "nslookup -type=TXT canadaka.net" and it returns: Server: google-public-dns-a.google.com Address: 8.8.8.8 Non-authoritative answer: canadaka.net text = "v=spf1 a include:_spf.google.com ~all" One strange thing I found is i'm unable to ping hotmail.com or msn.com or do a "telnet mail.hotmail.com 25". I am able to ping gmail.com and many other domains I tried. I tried changing my DNS servers to Google's Public DNS and did a ipconfig /flushdns but that had no effect. I am however able to connect with telnet to mx1.hotmail.com This is what the email headers look like when I send to a Google email server and I receive the email with no troubles. You can see that SPF is passing. Delivered-To: [email protected] Received: by 10.146.168.12 with SMTP id q12cs91243yae; Sun, 27 Feb 2011 18:01:49 -0800 (PST) Received: by 10.43.48.7 with SMTP id uu7mr4292541icb.68.1298858509242; Sun, 27 Feb 2011 18:01:49 -0800 (PST) Return-Path: Received: from canadaka.net ([66.199.162.177]) by mx.google.com with ESMTP id uh9si8493137icb.127.2011.02.27.18.01.45; Sun, 27 Feb 2011 18:01:48 -0800 (PST) Received-SPF: pass (google.com: domain of [email protected] designates 66.199.162.177 as permitted sender) client-ip=66.199.162.177; Authentication-Results: mx.google.com; spf=pass (google.com: domain of [email protected] designates 66.199.162.177 as permitted sender) [email protected] Message-Id: <[email protected] Received: from coruscant ([127.0.0.1]:12907) by canadaka.net with [XMail 1.27 ESMTP Server] id for from ; Sun, 27 Feb 2011 18:01:29 -0800 Date: Sun, 27 Feb 2011 18:01:29 -0800 Subject: Test To: [email protected] From: XXXX Reply-To: [email protected] X-Mailer: PHP/5.2.13 I can send to gmail and other email services fine. I don't know what i'm doing wrong! UPDATE 1 I have been removed from hotmails IP block and am now able to send emails to hotmail, but they are all going directly to the JUNK folder. UPDATE 2 I used Telnet to send a test message to port25.com, seems my SPF is not being detected. Result: neutral (SPF-Result: None) canadaka.net. SPF (no records) canadaka.net. TXT (no records) I do have a TXT record, its been there for years, I did change it a week ago. Other sites that allow you to check your SPF detect it, but some others like Microsofts Wizard doesn't. This iw what my SPF record in my xname.org DNS file looks like: canadaka.net. 86400 IN TXT "v=spf1 a include:_spf.google.com ~all" I did have a nameserver as my 4th option that doens't have the TXT records since it doens't support it. So I removed it from the list and instead added wtfdns.com as my 4th adn 5th nameservers, which does support TXT.

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  • Cisco VPN disconnects after 5 seconds with error 422

    - by Marius
    I'm trying to connect to my university's server with VPN using Cisco VPN Client version 5.0.04, but after 5 seconds it disconnects with the error message 422: Lost contact with the secure gateway. Check your connection. From my research on the net it seems this could be because it tries to find my IP, and finds out that this is 127.0.0.1. Then 5 seconds later it discovers that I have a new IP (my actual IP), and it disconnects because I'm not allowed to change IP. Does anyone know how I could fix this, or if there is another reason i get this error? Update I looked through the log, and found this error, which confirms what I thought, except it gets the correct IP first, then changes it to localhost. 87 18:56:53.250 08/24/09 Sev=Warning/3 CM/0xA3100027 Adapter address changed from 149.171.237.25. Current address(es): 127.0.0.1.

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  • Setting alias for DynDNS domain

    - by metalball
    Hey all, I've created DynDNS domain for testing my local sites, and i'm having trouble with pointing to root domain. From my registrar (GoDaddy) I've created a CNAME for www to point my example.dyndns.com so going to url www.example.com I'm reaching my site. But if I'm going to example.com I'm reaching to the IP of the A record. I can't set the IP for the A record to be my IP because I have dynamic IP, and it changes constatly, and I can't point the A record to domain, only IP. When trying to create CNAME record @ to point example.dyndns.com I'm getting error "A record of a different type exists for the hostname @, could not create CNAME" The only record using the '@' host are NS record, which I can't delete, and when tried to set another NS record with @ point to example.dyndns.com, I've lost connection to my site :) So what can I do to get example.com url reach my site? Thanx!

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  • freebsd ipfw tablearg.

    - by Shamanu4
    Hello. I'm configuring freebsd firewall and have such situation: 51000 pipe tablearg ip from not table(17) to table(20) out xmit ng* 51010 pipe tablearg ip from table(21) to not table(17) in recv ng* 51020 pipe tablearg ip from any to table(18) out xmit ng* 51030 pipe tablearg ip from table(19) to any in recv ng* tables 18,19,20,21 have client ip addresses and pipe numbers table 17 list of networks. rules 51020 and 51030 work fine but what is going at 51000 and 51010 ? How to determine firewall to take pipe number from tables 20 and 21 - not from 17 ?

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  • IIS replaces redirect status header from PHP with 302 Redirect

    - by IP
    Hello I hope I am posting this in the correct place... I'm having an issue with a 301 redirect in php. Looking at the headers, if I do a simple 301 redirect, it actually appears as a 302 redirect which is not what I am after. This is the php code: header("Status: 301 Moved Permanently"); header('Location: newurl'); It is running on the latest version of php, IIS7 and uses the FastCGI module (which is apparently where this bug could exist). A quick Google finds other people with the same problem, but no actual solution. http://www.mombu.com/php/bugs-forum/t-301-redirect-returning-302-instead-3090775.html http://forums.iis.net/p/1158431/1907156.aspx Many thanks! Paul

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  • rhel/centos vs. ubuntu (possibly other debian-based systems) linux in handling duplicate ips in the same subnet

    - by johnshen64
    This has bothered me for quite a while but I never found out why or how to change the behavior. ip duplicates could be caused by typos or dhcp errors etc., but they do occur from time to time. in rpm-based systems such as centos, the old server with the duplicate ip wins, and the new server will get an error in bringing up the nic (ip address already used). this is somewhat harmless because we can just fix the system that is coming up. ubuntu only the other hand happily grabs the used ip for itself and leave the old server/device without a valid ip. this is the more dangerous behavior because it causes outages. what i want is to change the ubuntu behavior to that of the centos/rhel so would appreciate any help.

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  • Ubuntu server 12.04 E: Unable to locate package noip2

    - by cesar
    I just Installed Ubuntu server 12.04 and I want to install no-ip I ran as root: sudo apt-get install noip2 and I got this: root@topcat:/var# sudo apt-get install noip2 Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package noip2 I also tried with:wget htt://www.no-ip.com/client/linux/noip-duc-linux.tar.gz but I got: wget: unable to resolve host address `www.no-ip.com' Does somebody can help me?, I am new in Ubuntu

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  • DNS question and Google PageRank from domains

    - by Beck
    I'm not so good at dns at all :) Just basics. A while ago i have noticed, that my blog have different Page Ranks, PR 3 for domain www.example.com and PR 1 for domain example.com. In dns records i have this setup: A - IP - www.example.com A - same IP - example.com Should i replace this record "A - same IP - example.com" with row with CNAME instead of A? Like that: CNAME - same IP - example.com - alias www.example.com Will this combine Page Rank value of both domains? Or i can just create 302 redirection inside .htaccess file, verify example.com(without www) inside Google Webmaster Tools as my domain and inside www.example.com options set as main domain? Thanks ;)

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  • why I can not install Gphpedit

    - by Mohamed Samir Khalil
    why I can not install Gphpedit and I get this errors: Failed to fetch //http://security.ubuntu.com/ubuntu/pool/main/w/webkit/libjavascriptcoregtk-1.0-0_1.8.1-0ubuntu0.12.04.1_amd64.deb 404 Not Found [IP: 91.189.92.190 80] Failed to fetch //http://security.ubuntu.com/ubuntu/pool/main/w/webkit/libwebkitgtk-1.0-common_1.8.1-0ubuntu0.12.04.1_all.deb 404 Not Found [IP: 91.189.92.190 80] Failed to fetch //http://security.ubuntu.com/ubuntu/pool/main/w/webkit/libwebkitgtk-1.0-0_1.8.1-0ubuntu0.12.04.1_amd64.deb 404 Not Found [IP: 91.189.92.190 80]

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  • Bonding: works only from one link

    - by Crazy_Bash
    I would like to install bonding with 4 links. but only one of them is active. eth4 is always active. the others simply don't work. those are my configs: DEVICE="eth2" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth3" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth4" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE="eth5" BOOTPROTO="none" MASTER=bond0 SLAVE=yes USERCTL=no NM_CONTROLLED="no" ONBOOT="yes" DEVICE=bond0 IPADDR=<ip> BROADCAST=<ip> NETWORK=<ip> GATEWAY=<ip> NETMASK=<ip> USERCTL=no BOOTPROTO=none ONBOOT=yes NM_CONTROLLED=no /etc/modprobe.d/bonding.conf alias bond0 bonding options bond0 mode=4 miimon=100 updelay=200 #downdelay=200 xmit_hash_policy=layer3+4 lacp_rate=1 Linux: Linux 3.0.0+ #1 SMP Fri Oct 26 07:55:47 EEST 2012 x86_64 x86_64 x86_64 GNU/Linux what i've tried: downdelay=200 xmit_hash_policy=layer3+4 lacp_rate=1

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  • Port forwarding for VNC on Dynalink RTA1335 not working

    - by Curyous
    I've vnc-java running on an Ubuntu box, with the IP address 192.168.1.68, using port 5800 (because port 5900 is being used for normal VNC). If I connect to 192.168.1.68:5800 using another computer on the network, I can use VNC fine. Using www.whatismyip.com, I find out what my IP address from the outside world is, and if I go directly to that, I get to access my modem/router. If I try to navigate to that IP address, with ':5800' on the end, I get a "This web page is not available." error. I have port forwarding set up in the router as follows: Application Name External Packet Internal Host IP Address Protocol Port IP Address Port VNC ALL TCP/UDP 5800 192.168.1.68 5800 What else do I need to do to get this to work?

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  • how to connect virtual box os and local machine

    - by Nrew
    This question is in connection to this question asked by a user before: http://superuser.com/questions/73470/virtualbox-vdi-file-to-vmware On how to convert vdi to vmdk or vmx using vmware converter. How do I connect the windows xp that is in virtual box to the local computer (windows 7) in a network. Because I got this error while I tried following this instruction: Give the IP address, username and password of the remote machine that you would like to convert and then hit next I got this error in vmware converter: Unable to connect the specified host 10.0.2.15 which is the ip address of the xp machine inside virtual box. It also said that there is a network configuration problem. And when I inputted the ip address from whatismyip.com which should be the same as the ip address on local machine. I didn't get the previous error but I got another one, it said that: insufficient permissions to connect to "ip address" What solution can you suggest for this problem?

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  • Apache Rewrites not working due to Akamai

    - by nuttyket
    I have a website which is setup with akamai. My domain and subdomains are mapped onto an Akamai IP. I have written an Apache rewrite which does an internal URL X to another internal URL Y. This rewrite works fine as long as I am testing in my local setup or for those subdomains which are not mapped onto Akamai but directly onto my Public IP. My suspicion is that while rewriting the request apache is not able to resolve the IP of the app server correctly. When I add entries to my /etc/hosts file pointing the domain/subdomain to my internal IP the rewrites work. Now, I have a huge list of subdomains and it can grow as well. Is there another way to fix this problem without having to make entries in the /etc/hosts file ? I would much appreciate your thoughts.

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  • Can't communicate with Primary DNS Server

    - by horsley
    A computer, with Windows 7, can't access any website by domain suddenly. Whether this computer use a wired link or connect to the WLAN, The fault persists IP and DNS obtained automatically, and seems normal (ipconfig /all return the correct info) I can visit websites by using HTTP proxy The DNS server is available, other computer in my room works properly. I can ping myself, the gateway and any other IP, but domains I can use nslookup and obtain the correct IP info There are some error information in the event log about dns client events explaining the client can not verify the DNS server available Windows network diagnosis explain that Windows can't communicate with the device or resource (Primary DNS Server) I guess the dns client should be blame. I tried to do the following things but the fault persist. Reinstall the driver of network adapter Reset TCP/IP (netsh int ip reset) Reset Winsock (netsh winsock reset) Reset LSP I don't want to reinstall the whole os, what should I do?

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  • fail2ban and denyhosts constantly ban me on Ubuntu

    - by Trey Parkman
    I just got an Ubuntu instance on Linode. To secure the SSH on it, I installed fail2ban (using apt-get), but then had a problem: fail2ban kept banning my IP (for limited durations, thankfully) even though I was entering the correct password. So I removed fail2ban and installed denyhosts instead. Same problem, but more severe: It seems like every time I SSH in, my IP gets banned. I remove it from /etc/hosts.deny, restart denyhosts and log in again, and my IP gets banned again. The only explanation I can think of is that I've been SSH-ing in as root (yes, yes, I know); maybe something is set somewhere that blocks anyone who SSH-es in as root, even if they log in successfully? This seems bizarre to me. Any ideas? (Whitelisting my IP is a temporary fix. I don't want to only be able to log on from one IP.)

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  • How to check command line requests routed thru TOR?

    - by Chris
    I think I have virtualbox set up so that all traffic originating from the guest OS is routed through TOR. TOR is only installed on the host OS and the web browsers on the guest OS all report TOR IP's in Europe when I test with seemyip.com. The host OS shows my real IP when going to the same sites. But I initiate a lot of requests from the Linux command line and I haven't been able to confirm to my satisfaction that these are routing through TOR, though I have no reason to think they do not. When I use this command I get no output from the guest OS, but my real IP from the host OS: dig myip.opendns.com @resolver1.opendns.com +short This bash file gives no output from either OS: #!/bin/bash echo Your external IP Address is: wget http://Www.whatismyip.com -O - -o /dev/null | grep '<TITLE>' | sed -r 's/<TITLE>WhatIsMyIP\.com \- //g' | sed -r 's/<\/TITLE>//g' exit 0 Suggestions?

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  • Bash window title not restored after exit

    - by forthrin
    I have a problem with the window title in the Terminal window on OS X: Start Terminal. Window title is "bash" Type "ssh external" to connect to an external server. Window title is "user@external:~" Type "exit". I am now back at my local machine, but the window title still says "user@external:~". How do I make the window title return to "bash", which I assume would be correct since I have logged out of the external server and returned to my local machine? My ~/.bash_profile has the same PS1 value: export PS1='\w$ '

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  • RIF PRD: Presentation syntax issues

    - by Charles Young
    Over Christmas I got to play a bit with the W3C RIF PRD and came across a few issues which I thought I would record for posterity. Specifically, I was working on a grammar for the presentation syntax using a GLR grammar parser tool (I was using the current CTP of ‘M’ (MGrammer) and Intellipad – I do so hope the MS guys don’t kill off M and Intellipad now they have dropped the other parts of SQL Server Modelling). I realise that the presentation syntax is non-normative and that any issues with it do not therefore compromise the standard. However, presentation syntax is useful in its own right, and it would be great to iron out any issues in a future revision of the standard. The main issues are actually not to do with the grammar at all, but rather with the ‘running example’ in the RIF PRD recommendation. I started with the code provided in Example 9.1. There are several discrepancies when compared with the EBNF rules documented in the standard. Broadly the problems can be categorised as follows: ·      Parenthesis mismatch – the wrong number of parentheses are used in various places. For example, in GoldRule, the RHS of the rule (the ‘Then’) is nested in the LHS (‘the If’). In NewCustomerAndWidgetRule, the RHS is orphaned from the LHS. Together with additional incorrect parenthesis, this leads to orphanage of UnknownStatusRule from the entire Document. ·      Invalid use of parenthesis in ‘Forall’ constructs. Parenthesis should not be used to enclose formulae. Removal of the invalid parenthesis gave me a feeling of inconsistency when comparing formulae in Forall to formulae in If. The use of parenthesis is not actually inconsistent in these two context, but in an If construct it ‘feels’ as if you are enclosing formulae in parenthesis in a LISP-like fashion. In reality, the parenthesis is simply being used to group subordinate syntax elements. The fact that an If construct can contain only a single formula as an immediate child adds to this feeling of inconsistency. ·      Invalid representation of compact URIs (CURIEs) in the context of Frame productions. In several places the URIs are not qualified with a namespace prefix (‘ex1:’). This conflicts with the definition of CURIEs in the RIF Datatypes and Built-Ins 1.0 document. Here are the productions: CURIE          ::= PNAME_LN                  | PNAME_NS PNAME_LN       ::= PNAME_NS PN_LOCAL PNAME_NS       ::= PN_PREFIX? ':' PN_LOCAL       ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* PN_CHARS)? PN_CHARS       ::= PN_CHARS_U                  | '-' | [0-9] | #x00B7                  | [#x0300-#x036F] | [#x203F-#x2040] PN_CHARS_U     ::= PN_CHARS_BASE                  | '_' PN_CHARS_BASE ::= [A-Z] | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6]                  | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF]                  | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF]                  | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD]                  | [#x10000-#xEFFFF] PN_PREFIX      ::= PN_CHARS_BASE ((PN_CHARS|'.')* PN_CHARS)? The more I look at CURIEs, the more my head hurts! The RIF specification allows prefixes and colons without local names, which surprised me. However, the CURIE Syntax 1.0 working group note specifically states that this form is supported…and then promptly provides a syntactic definition that seems to preclude it! However, on (much) deeper inspection, it appears that ‘ex1:’ (for example) is allowed, but would really represent a ‘fragment’ of the ‘reference’, rather than a prefix! Ouch! This is so completely ambiguous that it surely calls into question the whole CURIE specification.   In any case, RIF does not allow local names without a prefix. ·      Missing ‘External’ specifiers for built-in functions and predicates.  The EBNF specification enforces this for terms within frames, but does not appear to enforce (what I believe is) the correct use of External on built-in predicates. In any case, the running example only specifies ‘External’ once on the predicate in UnknownStatusRule. External() is required in several other places. ·      The List used on the LHS of UnknownStatusRule is comma-delimited. This is not supported by the EBNF definition. Similarly, the argument list of pred:list-contains is illegally comma-delimited. ·      Unnecessary use of conjunction around a single formula in DiscountRule. This is strictly legal in the EBNF, but redundant.   All the above issues concern the presentation syntax used in the running example. There are a few minor issues with the grammar itself. Note that Michael Kiefer stated in his paper “Rule Interchange Format: The Framework” that: “The presentation syntax of RIF … is an abstract syntax and, as such, it omits certain details that might be important for unambiguous parsing.” ·      The grammar cannot differentiate unambiguously between strategies and priorities on groups. A processor is forced to resolve this by detecting the use of IRIs and integers. This could easily be fixed in the grammar.   ·      The grammar cannot unambiguously parse the ‘->’ operator in frames. Specifically, ‘-’ characters are allowed in PN_LOCAL names and hence a parser cannot determine if ‘status->’ is (‘status’ ‘->’) or (‘status-’ ‘>’).   One way to fix this is to amend the PN_LOCAL production as follows: PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* ((PN_CHARS)-('-')))? However, unilaterally changing the definition of this production, which is defined in the SPARQL Query Language for RDF specification, makes me uncomfortable. ·      I assume that the presentation syntax is case-sensitive. I couldn’t find this stated anywhere in the documentation, but function/predicate names do appear to be documented as being case-sensitive. ·      The EBNF does not specify whitespace handling. A couple of productions (RULE and ACTION_BLOCK) are crafted to enforce the use of whitespace. This is not necessary. It seems inconsistent with the rest of the specification and can cause parsing issues. In addition, the Const production exhibits whitespaces issues. The intention may have been to disallow the use of whitespace around ‘^^’, but any direct implementation of the EBNF will probably allow whitespace between ‘^^’ and the SYMSPACE. Of course, I am being a little nit-picking about all this. On the whole, the EBNF translated very smoothly and directly to ‘M’ (MGrammar) and proved to be fairly complete. I have encountered far worse issues when translating other EBNF specifications into usable grammars.   I can’t imagine there would be any difficulty in implementing the same grammar in Antlr, COCO/R, gppg, XText, Bison, etc. A general observation, which repeats a point made above, is that the use of parenthesis in the presentation syntax can feel inconsistent and un-intuitive.   It isn’t actually inconsistent, but I think the presentation syntax could be improved by adopting braces, rather than parenthesis, to delimit subordinate syntax elements in a similar way to so many programming languages. The familiarity of braces would communicate the structure of the syntax more clearly to people like me.  If braces were adopted, parentheses could be retained around ‘var (frame | ‘new()’) constructs in action blocks. This use of parenthesis feels very LISP-like, and I think that this is my issue. It’s as if the presentation syntax represents the deformed love-child of LISP and C. In some places (specifically, action blocks), parenthesis is used in a LISP-like fashion. In other places it is used like braces in C. I find this quite confusing. Here is a corrected version of the running example (Example 9.1) in compliant presentation syntax: Document(    Prefix( ex1 <http://example.com/2009/prd2> )    (* ex1:CheckoutRuleset *)  Group rif:forwardChaining (     (* ex1:GoldRule *)    Group 10 (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"Silver"])        (Forall ?shoppingCart such that ?customer[ex1:shoppingCart->?shoppingCart]           (If Exists ?value (And(?shoppingCart[ex1:value->?value]                                  External(pred:numeric-greater-than-or-equal(?value 2000))))            Then Do(Modify(?customer[ex1:status->"Gold"])))))      (* ex1:DiscountRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Or( ?customer[ex1:status->"Silver"]                ?customer[ex1:status->"Gold"])         Then Do ((?s ?customer[ex1:shoppingCart-> ?s])                  (?v ?s[ex1:value->?v])                  Modify(?s [ex1:value->External(func:numeric-multiply (?v 0.95))]))))      (* ex1:NewCustomerAndWidgetRule *)    Group (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"New"] )        (If Exists ?shoppingCart ?item                   (And(?customer[ex1:shoppingCart->?shoppingCart]                        ?shoppingCart[ex1:containsItem->?item]                        ?item # ex1:Widget ) )         Then Do( (?s ?customer[ex1:shoppingCart->?s])                  (?val ?s[ex1:value->?val])                  (?voucher ?customer[ex1:voucher->?voucher])                  Retract(?customer[ex1:voucher->?voucher])                  Retract(?voucher)                  Modify(?s[ex1:value->External(func:numeric-multiply(?val 0.90))]))))      (* ex1:UnknownStatusRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Not(Exists ?status                       (And(?customer[ex1:status->?status]                            External(pred:list-contains(List("New" "Bronze" "Silver" "Gold") ?status)) )))         Then Do( Execute(act:print(External(func:concat("New customer: " ?customer))))                  Assert(?customer[ex1:status->"New"]))))  ) )   I hope that helps someone out there :-)

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  • Windows XP waits for usb drive on almost every operation.

    - by Tomasz Kowalczyk
    Hello everyone, I have a problem with my Windows XP operating system, particularly with the USB device that is plugged in - 1TB WD My Book external drive. I haven't found any information about such behaviour when searching in Internet, so I have to ask You. The problem is: when I am using computer, especially during work (programming), when I try to access any information on a hard disk ("internal" one), Windows seems to "consult" it with the external drive. For example, when I open file selection dialog window, if I try to change directory, system activates external drive, reads something (I hear the disk's operational noise) and after some seconds of such pause it makes the operations I requested. There are many situations in which I can reproduce this behavior - opening My Computer, shutting down system, opening partition folder from My Computer - every operation involves the usage of external drive. Please understand me properly - this is not something that happens EVERY time, but at least "many" times a day. What causes such behavior and how can I "turn off" external drive when it's not needed? Thanks in advance for your answers.

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