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• Installed Ubuntu 14.04LTS

  - by user291729

  On my laptop which came pre-installed with Windows 8.1. Felt I needed to see the competition for myself to establish which was a better OS. So I followed the channels to dual boot. All seemed fine and I accessed Ubuntu with no issues after selecting this from the menu to select the OS. I should add that the boot method was changed to legacy. However, since using Ubuntu, I no longer have the ability to select the OS. The laptop simply logs straight into Ubuntu. I therefore attempted to access the recovery options, only it appears the Windows 8 bootloader has somehow been corrupted as I am now told to use the Windows 8 recovery disc (which, as this was pre-installed - I do not have). Left with no other alternative, I have scoured these forums without success, and so I am hoping someone in the know (or who has experienced similar) can help. I have tried boot repair again without success. On rebooting I am only presented with a basic splash screen asking me to select Ubuntu, Memtest, Windows 8 Recovery or Windows 8 Bootloader (The bootloaders again require I insert the disc). I have tried Code: cat /boot/grub/grub.cfg df -h sudo fdisk -l cat /proc/partitions # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi if [ "${next_entry}" ] ; then set default="${next_entry}" set next_entry= save_env next_entry set boot_once=true else set default="0" fi if [ x"${feature_menuentry_id}" = xy ]; then menuentry_id_option="--id" else menuentry_id_option="" fi export menuentry_id_option if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { if [ x$feature_all_video_module = xy ]; then insmod all_video else insmod efi_gop insmod efi_uga insmod ieee1275_fb insmod vbe insmod vga insmod video_bochs insmod video_cirrus fi } if [ x$feature_default_font_path = xy ] ; then font=unicode else insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi font="/usr/share/grub/unicode.pf2" fi if loadfont $font ; then set gfxmode=800x600 load_video insmod gfxterm set locale_dir=$prefix/locale set lang=en_GB insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ] ; then set timeout=-1 else if [ x$feature_timeout_style = xy ] ; then set timeout_style=menu set timeout=20 # Fallback normal timeout code in case the timeout_style feature is # unavailable. else set timeout=20 fi fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi linux /boot/vmlinuz-3.13.0-29-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro vga=789 quiet quiet splash $vt_handoff initrd /boot/initrd.img-3.13.0-29-generic } submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { menuentry 'Ubuntu, with Linux 3.13.0-29-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-29-generic-advanced-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi echo 'Loading Linux 3.13.0-29-generic ...' linux /boot/vmlinuz-3.13.0-29-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro vga=789 quiet quiet splash $vt_handoff echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-29-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-29-generic-recovery-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi echo 'Loading Linux 3.13.0-29-generic ...' linux /boot/vmlinuz-3.13.0-29-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro recovery nomodeset vga=789 quiet echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-24-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-24-generic-advanced-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi echo 'Loading Linux 3.13.0-24-generic ...' linux /boot/vmlinuz-3.13.0-24-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro vga=789 quiet quiet splash $vt_handoff echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-24-generic } menuentry 'Ubuntu, with Linux 3.13.0-24-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-24-generic-recovery-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi echo 'Loading Linux 3.13.0-24-generic ...' linux /boot/vmlinuz-3.13.0-24-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro recovery nomodeset vga=789 quiet echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-24-generic } } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry 'Memory test (memtest86+)' { insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi knetbsd /boot/memtest86+.elf } menuentry 'Memory test (memtest86+, serial console 115200)' { insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry 'Windows Recovery Environment (loader) (on /dev/sda2)' --class windows --class os $menuentry_id_option 'osprober-chain-7A6A69D66A698FA5' { insmod part_gpt insmod ntfs set root='hd0,gpt2' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 --hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2 7A6A69D66A698FA5 else search --no-floppy --fs-uuid --set=root 7A6A69D66A698FA5 fi drivemap -s (hd0) ${root} chainloader +1 } menuentry 'Windows 8 (loader) (on /dev/sda3)' --class windows --class os $menuentry_id_option 'osprober-chain-8C88-80F7' { insmod part_gpt insmod fat set root='hd0,gpt3' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt3 --hint-efi=hd0,gpt3 --hint-baremetal=ahci0,gpt3 8C88-80F7 else search --no-floppy --fs-uuid --set=root 8C88-80F7 fi drivemap -s (hd0) ${root} chainloader +1 } set timeout_style=menu if [ "${timeout}" = 0 ]; then set timeout=10 fi ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/30_uefi-firmware ### ### END /etc/grub.d/30_uefi-firmware ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f ${config_directory}/custom.cfg ]; then source ${config_directory}/custom.cfg elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi if [ "${next_entry}" ] ; then set default="${next_entry}" set next_entry= save_env next_entry set boot_once=true else set default="0" fi if [ x"${feature_menuentry_id}" = xy ]; then menuentry_id_option="--id" else menuentry_id_option="" fi export menuentry_id_option if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { if [ x$feature_all_video_module = xy ]; then insmod all_video else insmod efi_gop insmod efi_uga insmod ieee1275_fb insmod vbe insmod vga insmod video_bochs insmod video_cirrus fi } if [ x$feature_default_font_path = xy ] ; then font=unicode else insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi font="/usr/share/grub/unicode.pf2" fi if loadfont $font ; then set gfxmode=800x600 load_video insmod gfxterm set locale_dir=$prefix/locale set lang=en_GB insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ] ; then set timeout=-1 else if [ x$feature_timeout_style = xy ] ; then set timeout_style=menu set timeout=20 # Fallback normal timeout code in case the timeout_style feature is # unavailable. else set timeout=20 fi fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi linux /boot/vmlinuz-3.13.0-29-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro vga=789 quiet quiet splash $vt_handoff initrd /boot/initrd.img-3.13.0-29-generic } submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { menuentry 'Ubuntu, with Linux 3.13.0-29-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-29-generic-advanced-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi echo 'Loading Linux 3.13.0-29-generic ...' linux /boot/vmlinuz-3.13.0-29-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro vga=789 quiet quiet splash $vt_handoff echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-29-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-29-generic-recovery-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi echo 'Loading Linux 3.13.0-29-generic ...' linux /boot/vmlinuz-3.13.0-29-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro recovery nomodeset vga=789 quiet echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-29-generic } menuentry 'Ubuntu, with Linux 3.13.0-24-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-24-generic-advanced-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi echo 'Loading Linux 3.13.0-24-generic ...' linux /boot/vmlinuz-3.13.0-24-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro vga=789 quiet quiet splash $vt_handoff echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-24-generic } menuentry 'Ubuntu, with Linux 3.13.0-24-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-24-generic-recovery-d2f10f36-e3bb-4d83-a9b8-5d456fc454ad' { recordfail load_video insmod gzio insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi echo 'Loading Linux 3.13.0-24-generic ...' linux /boot/vmlinuz-3.13.0-24-generic root=UUID=d2f10f36-e3bb-4d83-a9b8-5d456fc454ad ro recovery nomodeset vga=789 quiet echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.13.0-24-generic } } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry 'Memory test (memtest86+)' { insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi knetbsd /boot/memtest86+.elf } menuentry 'Memory test (memtest86+, serial console 115200)' { insmod part_gpt insmod ext2 set root='hd0,gpt9' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt9 --hint-efi=hd0,gpt9 --hint-baremetal=ahci0,gpt9 d2f10f36-e3bb-4d83-a9b8-5d456fc454ad else search --no-floppy --fs-uuid --set=root d2f10f36-e3bb-4d83-a9b8-5d456fc454ad fi linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry 'Windows Recovery Environment (loader) (on /dev/sda2)' --class windows --class os $menuentry_id_option 'osprober-chain-7A6A69D66A698FA5' { insmod part_gpt insmod ntfs set root='hd0,gpt2' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 --hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2 7A6A69D66A698FA5 else search --no-floppy --fs-uuid --set=root 7A6A69D66A698FA5 fi drivemap -s (hd0) ${root} chainloader +1 } menuentry 'Windows 8 (loader) (on /dev/sda3)' --class windows --class os $menuentry_id_option 'osprober-chain-8C88-80F7' { insmod part_gpt insmod fat set root='hd0,gpt3' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt3 --hint-efi=hd0,gpt3 --hint-baremetal=ahci0,gpt3 8C88-80F7 else search --no-floppy --fs-uuid --set=root 8C88-80F7 fi drivemap -s (hd0) ${root} chainloader +1 } set timeout_style=menu if [ "${timeout}" = 0 ]; then set timeout=10 fi ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/30_uefi-firmware ### ### END /etc/grub.d/30_uefi-firmware ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f ${config_directory}/custom.cfg ]; then source ${config_directory}/custom.cfg elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### john@john-SVE1713Y1EB:~$ ^C john@john-SVE1713Y1EB:~$ ^C john@john-SVE1713Y1EB:~$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda9 84G 7.1G 73G 9% / none 4.0K 0 4.0K 0% /sys/fs/cgroup udev 3.9G 4.0K 3.9G 1% /dev tmpfs 794M 1.4M 793M 1% /run none 5.0M 0 5.0M 0% /run/lock none 3.9G 80K 3.9G 1% /run/shm none 100M 52K 100M 1% /run/user /dev/sdc1 7.5G 2.2G 5.4G 29% /media/john/DYLANMUSIC /dev/sr0 964M 964M 0 100% /media/john/Ubuntu 14.04 LTS amd64 /dev/sdb1 1.9T 892G 972G 48% /media/john/Storage Main WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted. Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x4e2ccf75 Device Boot Start End Blocks Id System /dev/sda1 1 1953525167 976762583+ ee GPT Partition 1 does not start on physical sector boundary. Disk /dev/sdc: 8011 MB, 8011120640 bytes 41 heads, 41 sectors/track, 9307 cylinders, total 15646720 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc3072e18 Device Boot Start End Blocks Id System /dev/sdc1 8064 15646719 7819328 b W95 FAT32 Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc7d968ff Device Boot Start End Blocks Id System /dev/sdb1 64 3907029119 1953514528 7 HPFS/NTFS/exFAT major minor #blocks name 8 0 976762584 sda 8 1 266240 sda1 8 2 1509376 sda2 8 3 266240 sda3 8 4 131072 sda4 8 5 841012780 sda5 8 6 358400 sda6 8 7 35376128 sda7 8 8 1024 sda8 8 9 89501696 sda9 8 10 8337408 sda10 11 0 987136 sr0 8 32 7823360 sdc 8 33 7819328 sdc1 8 16 1953514584 sdb 8 17 1953514528 sdb1 I am no expert on this and I'm at a loss as how to correct this without having to re-format everything and reinstall Windows 8. However, if I'm to try using Ubuntu again then there is the risk this problem may come back. Again, I did not do anything manually - the installer did everything (with the exception of changing the boot to Legacy to allow the booting of another bootloader). LiveCD works but doesn't give me the options that I've seen here and as mentioned earlier, only boot recovery only gives me the options as mentioned earlier. Also this fails to load via USB (possibly because HDD comes before USB in the boot order?). Being used to a Windows environment, the Ubuntu (and Linux) environment is a dive at a less than comfortable depth at present (but one I fully intend to get to grips with - especially the commands being more common via Terminal). I very much appreciate the help with this guys.

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• Creating generic list of instances of a class.

  - by Jim Branson

  I have several projects where I build a dictionary from a small class. I'm using C# 2008, Visual studio 2008 and .net 3.5 This is the code: namespace ReportsTest { class Junk { public static Dictionary<string, string> getPlatKeys() { Dictionary<string, string> retPlatKeys = new Dictionary<string, string>(); SqlConnection conn = new SqlConnection("Data Source=JB55LTARL;Initial Catalog=HldiReports;Integrated Security=True"); SqlDataReader Dr = null; conn.Open(); SqlCommand cmnd = new SqlCommand("SELECT Make, Series, RedesignYear, SeriesName FROM CompPlatformKeys", conn); Dr = cmnd.ExecuteReader(); while (Dr.Read()) { utypPlatKeys rec = new utypPlatKeys(Dr); retPlatKeys.Add(rec.Make + rec.Series + rec.RedesignYear, rec.SeriesName); } conn = null; Dr = null; return retPlatKeys; } } public class utypPlatKeys { public string Make { get; set; } public string Series { get; set; } public string RedesignYear { get; set; } public string SeriesName { get; set; } public utypPlatKeys(SqlDataReader dr) { this.Make = dr.GetInt16(dr.GetOrdinal("Make")).ToString("D3"); this.Series = dr.GetInt16(dr.GetOrdinal("Series")).ToString("D3"); this.RedesignYear = dr.GetInt16(dr.GetOrdinal("RedesignYear")).ToString(); this.SeriesName = dr["SeriesName"].ToString(); } } } The immediate window shows all of the entries in retPlatKeys and if you hover over retPlatKeys after loading it indicates the number of elements like this: "retPlatKeys| Count = 923 which is correct. I went to create a new project using this pattern only now the immediate window says retPlatKeys is out of scope and hovering over retPlatKeys after loading I get something like retPlatKeys|0x0000000002578900. Any help is greatly appreciated.

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• Resolving a Generic with a Generic parameter in Castle Windsor

  - by Aaron Fischer

  I am trying to register a type like IRequestHandler1[GenericTestRequest1[T]] which will be implemented by GenericTestRequestHandler`1[T] but I am currently getting an error from Windsor "Castle.MicroKernel.ComponentNotFoundException : No component for supporting the service " Is this type of operation supported? Or is it to far removed from the suppored register( Component.For(typeof( IList<).ImplementedBy( typeof( List< ) ) ) below is an example of a breaking test. ////////////////////////////////////////////////////// public interface IRequestHandler{} public interface IRequestHandler<TRequest> : IRequestHandler where TRequest : Request{} public class GenericTestRequest<T> : Request{} public class GenericTestRequestHandler<T> : RequestHandler<GenericTestRequest<T>>{} [TestFixture] public class ComponentRegistrationTests{ [Test] public void DoNotAutoRegisterGenericRequestHandler(){ var IOC = new Castle.Windsor.WindsorContainer(); var type = typeof( IRequestHandler<> ).MakeGenericType( typeof( GenericTestRequest<> ) ); IOC.Register( Component.For( type ).ImplementedBy( typeof( GenericTestRequestHandler<> ) ) ); var requestHandler = IoC.Container.Resolve( typeof(IRequestHandler<GenericTestRequest<String>>)); Assert.IsInstanceOf <IRequestHandler<GenericTestRequest<String>>>( requestHandler ); Assert.IsNotNull( requestHandler ); } }

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• Generic List<T> as IEnumerable<object>

  - by Avi

  I'm trying to do cast a List to an IEnumerable, so I can verify that different lists are not null or empty: Suppose myList is a List < T . Then in the caller code I wanted: Validator.VerifyNotNullOrEmpty(myList as IEnumerable<object>, @"myList", @"ClassName.MethodName"); The valdiating code would be: public static void VerifyNotNullOrEmpty(IEnumerable<object> theIEnumerable, string theIEnumerableName, string theVerifyingPosition) { string errMsg = theVerifyingPosition + " " + theIEnumerableName; if (theIEnumerable == null) { errMsg += @" is null"; Debug.Assert(false); throw new ApplicationException(errMsg); } else if (theIEnumerable.Count() == 0) { errMsg += @" is empty"; Debug.Assert(false); throw new ApplicationException(errMsg); } } However, this doens't work. It compiles, but theIEnumerable is null! Why?

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• Casting a non-generic type to a generic one

  - by John Sheehan

  I've got this class: class Foo { public string Name { get; set; } } And this class class Foo<T> : Foo { public T Data { get; set; } } Here's what I want to do: public Foo<T> GetSome() { Foo foo = GetFoo(); Foo<T> foot = (Foo<T>)foo; foot.Data = GetData<T>(); return foot; } What's the easiest way to convert Foo to Foo<T>? I can't cast directly InvalidCastException) and I don't want to copy each property manually (in my actual use case, there's more than one property) if I don't have to. Is a user-defined type conversion the way to go?

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• django generic view update/create: update works but create raises IntegrityError

  - by smarber

  I'm using CreateView and UpdateView directely into urls.py of my application whose name is dydict. In the file forms.py I'm using ModelForm and I'm exluding a couple of fields from being shown, some of which sould be set when either creating or updating. So, as mentioned in the title, update part works but create part doesn't which is obvious because required fields that I have exluded are sent empty which is not allowed in my case. So the question here is, how should I do to fill exluded fields into the file forms.py so that I don't have to override CreateView? Thanks in advance.

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• c# inheriting generic collection and serialization...

  - by Stecy

  Hi, The setup: class Item { private int _value; public Item() { _value = 0; } public int Value { get { return _value; } set { _value = value; } } } class ItemCollection : Collection<Item> { private string _name; public ItemCollection() { _name = string.Empty; } public string Name { get {return _name;} set {_name = value;} } } Now, trying to serialize using the following code fragment: ItemCollection items = new ItemCollection(); ... XmlSerializer serializer = new XmlSerializer(typeof(ItemCollection)); using (FileStream f = File.Create(fileName)) serializer.Serialize(f, items); Upon looking at the resulting XML I see that the ItemCollection.Name value is not there! I think what may be happening is that the serializer sees the ItemCollection type as a simple Collection thus ignoring any other added properties... Is there anyone having encountered such a problem and found a solution? Regards, Stécy

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• Explicitly instantiating a generic member function of a generic structure

  - by Dennis Zickefoose

  I have a structure with a template parameter, Stream. Within that structure, there is a function with its own template parameter, Type. If I try to force a specific instance of the function to be generated and called, it works fine, if I am in a context where the exact type of the structure is known. If not, I get a compile error. This feels like a situation where I'm missing a typename, but there are no nested types. I suspect I'm missing something fundamental, but I've been staring at this code for so long all I see are redheads, and frankly writing code that uses templates has never been my forte. The following is the simplest example I could come up with that illustrates the issue. #include <iostream> template<typename Stream> struct Printer { Stream& str; Printer(Stream& str_) : str(str_) { } template<typename Type> Stream& Exec(const Type& t) { return str << t << std::endl; } }; template<typename Stream, typename Type> void Test1(Stream& str, const Type& t) { Printer<Stream> out = Printer<Stream>(str); /****** vvv This is the line the compiler doesn't like vvv ******/ out.Exec<bool>(t); /****** ^^^ That is the line the compiler doesn't like ^^^ ******/ } template<typename Type> void Test2(const Type& t) { Printer<std::ostream> out = Printer<std::ostream>(std::cout); out.Exec<bool>(t); } template<typename Stream, typename Type> void Test3(Stream& str, const Type& t) { Printer<Stream> out = Printer<Stream>(str); out.Exec(t); } int main() { Test2(5); Test3(std::cout, 5); return 0; } As it is written, gcc-4.4 gives the following: test.cpp: In function 'void Test1(Stream&, const Type&)': test.cpp:22: error: expected primary-expression before 'bool' test.cpp:22: error: expected ';' before 'bool' Test2 and Test3 both compile cleanly, and if I comment out Test1 the program executes, and I get "1 5" as I expect. So it looks like there's nothing wrong with the idea of what I want to do, but I've botched something in the implementation. If anybody could shed some light on what I'm overlooking, it would be greatly appreciated.

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• Class hierarchy problem (with generic's variance!)

  - by devoured elysium

  The problem: class StatesChain : IState, IHasStateList { private TasksChain tasks = new TasksChain(); ... public IList<IState> States { get { return _taskChain.Tasks; } } IList<ITask> IHasTasksCollection.Tasks { get { return _taskChain.Tasks; } <-- ERROR! You can't do this in C#! I want to return an IList<ITask> from an IList<IStates>. } } Assuming the IList returned will be read-only, I know that what I'm trying to achieve is safe (or is it not?). Is there any way I can accomplish what I'm trying? I wouldn't want to try to implement myself the TasksChain algorithm (again!), as it would be error prone and would lead to code duplication. Maybe I could just define an abstract Chain and then implement both TasksChain and StatesChain from there? Or maybe implementing a Chain<T> class? How would you approach this situation? The Details: I have defined an ITask interface: public interface ITask { bool Run(); ITask FailureTask { get; } } and a IState interface that inherits from ITask: public interface IState : ITask { IState FailureState { get; } } I have also defined an IHasTasksList interface: interface IHasTasksList { List<Tasks> Tasks { get; } } and an IHasStatesList: interface IHasTasksList { List<Tasks> States { get; } } Now, I have defined a TasksChain, that is a class that has some code logic that will manipulate a chain of tasks (beware that TasksChain is itself a kind of ITask!): class TasksChain : ITask, IHasTasksList { IList<ITask> tasks = new List<ITask>(); ... public List<ITask> Tasks { get { return _tasks; } } ... } I am implementing a State the following way: public class State : IState { private readonly TaskChain _taskChain = new TaskChain(); public State(Precondition precondition, Execution execution) { _taskChain.Tasks.Add(precondition); _taskChain.Tasks.Add(execution); } public bool Run() { return _taskChain.Run(); } public IState FailureState { get { return (IState)_taskChain.Tasks[0].FailureTask; } } ITask ITask.FailureTask { get { return FailureState; } } } which, as you can see, makes use of explicit interface implementations to "hide" FailureTask and instead show FailureState property. The problem comes from the fact that I also want to define a StatesChain, that inherits both from IState and IHasStateList (and that also imples ITask and IHasTaskList, implemented as explicit interfaces) and I want it to also hide IHasTaskList's Tasks and only show IHasStateList's States. (What is contained in "The problem" section should really be after this, but I thought puting it first would be way more reader friendly). (pff..long text) Thanks!

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• generic identifier

  - by Werner

  Hi, as I probably do not describe the problem in the right terms, I was not able to get an answer with google. Please excuse! In the following code, I would like to replace 'hardcoded' identifier COMMENT with the variable editedField. How to do that? var editedField:String = event.dataField; if (model.multipleProcessingData[i][editedInformationProductNO].COMMENT != null{ ... }

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• Generic List created at runtime

  - by Perry

  Hi... i neeed something like this in C#.. have list in class but decide what will be in list during runtime class A { List data; Type typeOfDataInList; } public void FillData(DataTyp[] data) where DataTyp : struct { A a = new A(); A.vListuBudouDataTypu = typeof(DataTyp); A.data = new List(); A.AddRange(data); } Is this possible to do something like this ?

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• C# method generic params parameter bug?

  - by Mike M

  Hey, I appears to me as though there is a bug/inconsistency in the C# compiler. This works fine (first method gets called): public void SomeMethod(string message, object data); public void SomeMethod(string message, params object[] data); // .... SomeMethod("woohoo", item); Yet this causes "The call is ambiguous between the following methods" error: public void SomeMethod(string message, T data); public void SomeMethod(string message, params T[] data); // .... SomeMethod("woohoo", (T)item); I could just use the dump the first method entirely, but since this is a very performance sensitive library and the first method will be used about 75% of the time, I would rather not always wrap things in an array and instantiate an iterator to go over a foreach if there is only one item. Splitting into different named methods would be messy at best IMO. Thoughts?

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• C# Calling Methods in Generic Classes

  - by aip.cd.aish

  I am extending the ImageBox control from EmguCV. The control's Image property can be set to anything implementing the IImage interface. All of the following implement this interface: Image<Bgr, Byte> Image<Ycc, Byte> Image<Hsv, Byte> Now I want to call the Draw method on the object of the above type (what ever it may be). The problem is when I access the Image property, the return type is IImage. IImage does not implement the Draw method, but all of the above do. I believe I can cast the object of type IImage to one of the above (the right one) and I can access the Draw method. But how do I know what the right one is? If you have a better way of doing this, please suggest that as well.

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• How do i assigned the type of any object to a generic method in C#

  - by Usman

  Hi, Suppose that I have created a method like this private void Test<t>(t str) { } Now from another method i call it private void BtnClick() { string a = ""; test<Here I Want To assign The Type what ever the type of 'a' is>(); } How can I do this ?

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• c# Generic overloaded method dispatching ambiguous

  - by sebgod

  Hello, I just hit a situation where a method dispatch was ambiguous and wondered if anyone could explain on what basis the compiler (.NET 4.0.30319) chooses what overload to call interface IfaceA { } interface IfaceB<T> { void Add(IfaceA a); T Add(T t); } class ConcreteA : IfaceA { } class abstract BaseClassB<T> : IfaceB<T> { public virtual T Add(T t) { ... } public virtual void Add(IfaceA a) { ... } } class ConcreteB : BaseClassB<IfaceA> { // does not override one of the relevant methods } void code() { var concreteB = new ConcreteB(); // it will call void Add(IfaceA a) concreteB.Add(new ConcreteA()); } In any case, why does the compiler not warn me or even why does it compile? Thank you very much for any answers.

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• Cannot inherit from generic base class and specific interface using same type with generic constrain

  - by simendsjo

  Sorry about the strange title. I really have no idea how to express it any better... I get an error on the following snippet. I use the class Dummy everywhere. Doesn't the compiler understand the constraint I've added on DummyImplBase? Is this a compiler bug as it works if I use Dummy directly instead of setting it as a constraint? Error 1 'ConsoleApplication53.DummyImplBase' does not implement interface member 'ConsoleApplication53.IRequired.RequiredMethod()'. 'ConsoleApplication53.RequiredBase.RequiredMethod()' cannot implement 'ConsoleApplication53.IRequired.RequiredMethod()' because it does not have the matching return type of 'ConsoleApplication53.Dummy'. C:\Documents and Settings\simen\My Documents\Visual Studio 2008\Projects\ConsoleApplication53\ConsoleApplication53\Program.cs 37 27 ConsoleApplication53 public class Dummy { } public interface IRequired<T> { T RequiredMethod(); } public interface IDummyRequired : IRequired<Dummy> { void OtherMethod(); } public class RequiredBase<T> : IRequired<T> { public T RequiredMethod() { return default(T); } } public abstract class DummyImplBase<T> : RequiredBase<T>, IDummyRequired where T: Dummy { public void OtherMethod() { } }

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• Generic TypeIdenitifier convertion.How?

  - by John

  How do I convert the TypeIdenitifier to a class type? I need to use implicit convertion. type TMyChildArray<T>=class(TMyArray<T>) private FData:Array of T; procedure AddEnd(); end; TTypeIdenitifierParentClass=class(TAnotherParentClass) protected TestField:Cardinal; end; procedure TMyChildArray<T>.AddEnd(); var elem:T; begin for elem in Fdata do TTypeIdenitifierParentClass(elem).TestField:=0; end; I get "Invalid typecast" on the implicit convertion "TTypeIdenitifierParentClass(elem).TestField:=0;". The principle I want to use is that the TypeIdenitifier will represent a class that descends from TTypeIdenitifierParentClass.There are many class types,but all of them descend that class. How do I do this?

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• how to create property of type generic class?

  - by Anish

  public class SelectionList<T> : ObservableCollection<SelectionItem<T>> where T : IComparable<T> { // Code } public class SelectionItem<T> : INotifyPropertyChanged { // Code } I need to create a property which is of the type SelectionList...as follows: public SelectionList<string> Sports { get; set; }. But when I replace string with DataRowView, as public SelectionList<DataRowView> Sports { get; set; }. I am getting error. Please help

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• How to call a generic method through reflection

  - by milan

  Hi, is it possible to call with reflection a method with "explict type argument" <S> definition e.g. oObject.Cast<S>() ? where is: IList <P> oObject = new List <P>(); I tried with oObject.getType().InvokeMember( "Cast", BindingFlags.InvokeMethod, null, oObject, null) but it does not work, does anyone know why?

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• Pass Extra Parameters to JavaScript Callback Function

  - by BRADINO

  Here is a simple example of a function that takes a callback function as a parameter. query.send(handleQueryResponse); function handleQueryResponse(response){      alert('Processing...'); } If you wanted to pass extra variables to the callback function, you can do it like this. var param1 = 'something'; var param2 ='something else'; query.send(function(response) { handleQueryResponse(response, param1, param2) }); function handleQueryResponse(response,param1,param2){      alert('Processing...');      alert(param1);      alert(param2); }

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• Can't install or update Ubuntu after using parameter acpi_osi = Linux

  - by Lucas Leitão

  I recently had an issue with my acer 4736z notebook because I was having a blank screen after booting the OS, then someone told me to use the parameter GRUB_CMDLINE_LINUX_DEFAULT = "quiet splash acpi_osi = Linux" after quiet splash inside the grub. It worked for me, but since then I can't install a thing or update anything on Linux because it says Removing linux-image-extra-3.5.0-17-generic ... Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.5.0-17-generic /boot/vmlinuz-3.5.0-17-generic update-initramfs: Deleting /boot/initrd.img-3.5.0-17-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.5.0-17-generic /boot/vmlinuz-3.5.0-17-generic /usr/sbin/grub-mkconfig: 11: /etc/default/grub: GRUB_CMDLINE_LINUX_DEFAULT: not found run-parts: /etc/kernel/postrm.d/zz-update-grub exited with return code 127 Failed to process /etc/kernel/postrm.d at /var/lib/dpkg/info/linux-image-extra-3.5.0-17-generic.postrm line 328. dpkg: erro ao processar linux-image-extra-3.5.0-17-generic (--remove): sub-processo script post-removal instalado retornou estado de saída de erro 1 Removendo linux-image-3.5.0-17-generic ... Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.5.0-17-generic /boot/vmlinuz-3.5.0-17-generic update-initramfs: Deleting /boot/initrd.img-3.5.0-17-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.5.0-17-generic /boot/vmlinuz-3.5.0-17-generic /usr/sbin/grub-mkconfig: 11: /etc/default/grub: GRUB_CMDLINE_LINUX_DEFAULT: not found run-parts: /etc/kernel/postrm.d/zz-update-grub exited with return code 127 Failed to process /etc/kernel/postrm.d at /var/lib/dpkg/info/linux-image-3.5.0-17-generic.postrm line 328. dpkg: erro ao processar linux-image-3.5.0-17-generic (--remove): sub-processo script post-removal instalado retornou estado de saída de erro 1 Erros foram encontrados durante o processamento de: linux-image-extra-3.5.0-17-generic linux-image-3.5.0-17-generic E: Sub-process /usr/bin/dpkg returned an error code (1) I already tried to remove older kernels but it gives me the same message. Do you have a clue about what should I do?

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• C#/.NET Little Wonders: The Predicate, Comparison, and Converter Generic Delegates

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. In the last three weeks, we examined the Action family of delegates (and delegates in general), the Func family of delegates, and the EventHandler family of delegates and how they can be used to support generic, reusable algorithms and classes. This week I will be completing my series on the generic delegates in the .NET Framework with a discussion of three more, somewhat less used, generic delegates: Predicate<T>, Comparison<T>, and Converter<TInput, TOutput>. These are older generic delegates that were introduced in .NET 2.0, mostly for use in the Array and List<T> classes.  Though older, it’s good to have an understanding of them and their intended purpose.  In addition, you can feel free to use them yourself, though obviously you can also use the equivalents from the Func family of delegates instead. Predicate<T> – delegate for determining matches The Predicate<T> delegate was a very early delegate developed in the .NET 2.0 Framework to determine if an item was a match for some condition in a List<T> or T[].  The methods that tend to use the Predicate<T> include: Find(), FindAll(), FindLast() Uses the Predicate<T> delegate to finds items, in a list/array of type T, that matches the given predicate. FindIndex(), FindLastIndex() Uses the Predicate<T> delegate to find the index of an item, of in a list/array of type T, that matches the given predicate. The signature of the Predicate<T> delegate (ignoring variance for the moment) is: 1: public delegate bool Predicate<T>(T obj); So, this is a delegate type that supports any method taking an item of type T and returning bool.  In addition, there is a semantic understanding that this predicate is supposed to be examining the item supplied to see if it matches a given criteria. 1: // finds first even number (2) 2: var firstEven = Array.Find(numbers, n => (n % 2) == 0); 3:  4: // finds all odd numbers (1, 3, 5, 7, 9) 5: var allEvens = Array.FindAll(numbers, n => (n % 2) == 1); 6:  7: // find index of first multiple of 5 (4) 8: var firstFiveMultiplePos = Array.FindIndex(numbers, n => (n % 5) == 0); This delegate has typically been succeeded in LINQ by the more general Func family, so that Predicate<T> and Func<T, bool> are logically identical.  Strictly speaking, though, they are different types, so a delegate reference of type Predicate<T> cannot be directly assigned to a delegate reference of type Func<T, bool>, though the same method can be assigned to both. 1: // SUCCESS: the same lambda can be assigned to either 2: Predicate<DateTime> isSameDayPred = dt => dt.Date == DateTime.Today; 3: Func<DateTime, bool> isSameDayFunc = dt => dt.Date == DateTime.Today; 4:  5: // ERROR: once they are assigned to a delegate type, they are strongly 6: // typed and cannot be directly assigned to other delegate types. 7: isSameDayPred = isSameDayFunc; When you assign a method to a delegate, all that is required is that the signature matches.  This is why the same method can be assigned to either delegate type since their signatures are the same.  However, once the method has been assigned to a delegate type, it is now a strongly-typed reference to that delegate type, and it cannot be assigned to a different delegate type (beyond the bounds of variance depending on Framework version, of course). Comparison<T> – delegate for determining order Just as the Predicate<T> generic delegate was birthed to give Array and List<T> the ability to perform type-safe matching, the Comparison<T> was birthed to give them the ability to perform type-safe ordering. The Comparison<T> is used in Array and List<T> for: Sort() A form of the Sort() method that takes a comparison delegate; this is an alternate way to custom sort a list/array from having to define custom IComparer<T> classes. The signature for the Comparison<T> delegate looks like (without variance): 1: public delegate int Comparison<T>(T lhs, T rhs); The goal of this delegate is to compare the left-hand-side to the right-hand-side and return a negative number if the lhs < rhs, zero if they are equal, and a positive number if the lhs > rhs.  Generally speaking, null is considered to be the smallest value of any reference type, so null should always be less than non-null, and two null values should be considered equal. In most sort/ordering methods, you must specify an IComparer<T> if you want to do custom sorting/ordering.  The Array and List<T> types, however, also allow for an alternative Comparison<T> delegate to be used instead, essentially, this lets you perform the custom sort without having to have the custom IComparer<T> class defined. It should be noted, however, that the LINQ OrderBy(), and ThenBy() family of methods do not support the Comparison<T> delegate (though one could easily add their own extension methods to create one, or create an IComparer() factory class that generates one from a Comparison<T>). So, given this delegate, we could use it to perform easy sorts on an Array or List<T> based on custom fields.  Say for example we have a data class called Employee with some basic employee information: 1: public sealed class Employee 2: { 3: public string Name { get; set; } 4: public int Id { get; set; } 5: public double Salary { get; set; } 6: } And say we had a List<Employee> that contained data, such as: 1: var employees = new List<Employee> 2: { 3: new Employee { Name = "John Smith", Id = 2, Salary = 37000.0 }, 4: new Employee { Name = "Jane Doe", Id = 1, Salary = 57000.0 }, 5: new Employee { Name = "John Doe", Id = 5, Salary = 60000.0 }, 6: new Employee { Name = "Jane Smith", Id = 3, Salary = 59000.0 } 7: }; Now, using the Comparison<T> delegate form of Sort() on the List<Employee>, we can sort our list many ways: 1: // sort based on employee ID 2: employees.Sort((lhs, rhs) => Comparer<int>.Default.Compare(lhs.Id, rhs.Id)); 3:  4: // sort based on employee name 5: employees.Sort((lhs, rhs) => string.Compare(lhs.Name, rhs.Name)); 6:  7: // sort based on salary, descending (note switched lhs/rhs order for descending) 8: employees.Sort((lhs, rhs) => Comparer<double>.Default.Compare(rhs.Salary, lhs.Salary)); So again, you could use this older delegate, which has a lot of logical meaning to it’s name, or use a generic delegate such as Func<T, T, int> to implement the same sort of behavior.  All this said, one of the reasons, in my opinion, that Comparison<T> isn’t used too often is that it tends to need complex lambdas, and the LINQ ability to order based on projections is much easier to use, though the Array and List<T> sorts tend to be more efficient if you want to perform in-place ordering. Converter<TInput, TOutput> – delegate to convert elements The Converter<TInput, TOutput> delegate is used by the Array and List<T> delegate to specify how to convert elements from an array/list of one type (TInput) to another type (TOutput).  It is used in an array/list for: ConvertAll() Converts all elements from a List<TInput> / TInput[] to a new List<TOutput> / TOutput[]. The delegate signature for Converter<TInput, TOutput> is very straightforward (ignoring variance): 1: public delegate TOutput Converter<TInput, TOutput>(TInput input); So, this delegate’s job is to taken an input item (of type TInput) and convert it to a return result (of type TOutput).  Again, this is logically equivalent to a newer Func delegate with a signature of Func<TInput, TOutput>.  In fact, the latter is how the LINQ conversion methods are defined. So, we could use the ConvertAll() syntax to convert a List<T> or T[] to different types, such as: 1: // get a list of just employee IDs 2: var empIds = employees.ConvertAll(emp => emp.Id); 3:  4: // get a list of all emp salaries, as int instead of double: 5: var empSalaries = employees.ConvertAll(emp => (int)emp.Salary); Note that the expressions above are logically equivalent to using LINQ’s Select() method, which gives you a lot more power: 1: // get a list of just employee IDs 2: var empIds = employees.Select(emp => emp.Id).ToList(); 3:  4: // get a list of all emp salaries, as int instead of double: 5: var empSalaries = employees.Select(emp => (int)emp.Salary).ToList(); The only difference with using LINQ is that many of the methods (including Select()) are deferred execution, which means that often times they will not perform the conversion for an item until it is requested.  This has both pros and cons in that you gain the benefit of not performing work until it is actually needed, but on the flip side if you want the results now, there is overhead in the behind-the-scenes work that support deferred execution (it’s supported by the yield return / yield break keywords in C# which define iterators that maintain current state information). In general, the new LINQ syntax is preferred, but the older Array and List<T> ConvertAll() methods are still around, as is the Converter<TInput, TOutput> delegate. Sidebar: Variance support update in .NET 4.0 Just like our descriptions of Func and Action, these three early generic delegates also support more variance in assignment as of .NET 4.0.  Their new signatures are: 1: // comparison is contravariant on type being compared 2: public delegate int Comparison<in T>(T lhs, T rhs); 3:  4: // converter is contravariant on input and covariant on output 5: public delegate TOutput Contravariant<in TInput, out TOutput>(TInput input); 6:  7: // predicate is contravariant on input 8: public delegate bool Predicate<in T>(T obj); Thus these delegates can now be assigned to delegates allowing for contravariance (going to a more derived type) or covariance (going to a less derived type) based on whether the parameters are input or output, respectively. Summary Today, we wrapped up our generic delegates discussion by looking at three lesser-used delegates: Predicate<T>, Comparison<T>, and Converter<TInput, TOutput>.  All three of these tend to be replaced by their more generic Func equivalents in LINQ, but that doesn’t mean you shouldn’t understand what they do or can’t use them for your own code, as they do contain semantic meanings in their names that sometimes get lost in the more generic Func name.   Tweet Technorati Tags: C#,CSharp,.NET,Little Wonders,delegates,generics,Predicate,Converter,Comparison

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• First languages with generic programming support

  - by oluies

  Which was the first language with generic programming support, and what was the first major staticly typed language (widely used) with generics support. Generics implement the concept of parameterized types to allow for multiple types. The term generic means "pertaining to or appropriate to large groups of classes." I have seen the following mentions of "first": First-order parametric polymorphism is now a standard element of statically typed programming languages. Starting with System F [20,42] and functional programming lan- guages, the constructs have found their way into mainstream languages such as Java and C#. In these languages, first-order parametric polymorphism is usually called generics. From "Generics of a Higher Kind", Adriaan Moors, Frank Piessens, and Martin Odersky Generic programming is a style of computer programming in which algorithms are written in terms of to-be-specified-later types that are then instantiated when needed for specific types provided as parameters. This approach, pioneered by Ada in 1983 From Wikipedia Generic Programming

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• First languages with generic programming support

  - by oluies

  Which was the first language with generic programming support, and what was the first major staticly typed language (widely used) with generics support. Generics implement the concept of parameterized types to allow for multiple types. The term generic means "pertaining to or appropriate to large groups of classes." I have seen the following mentions of "first": First-order parametric polymorphism is now a standard element of statically typed programming languages. Starting with System F [20,42] and functional programming lan- guages, the constructs have found their way into mainstream languages such as Java and C#. In these languages, first-order parametric polymorphism is usually called generics. From "Generics of a Higher Kind", Adriaan Moors, Frank Piessens, and Martin Odersky Generic programming is a style of computer programming in which algorithms are written in terms of to-be-specified-later types that are then instantiated when needed for specific types provided as parameters. This approach, pioneered by Ada in 1983 From Wikipedia Generic Programming

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• MZCrumbBar - Generic Breadcrumb controller

  Generic MFC Breadcrumb controller that shows a clickable breadcrumb list

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