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Friday, December 7, 2007

How Do I Add Temporary Swap Space?

This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).
In addition to a swap partition, Linux can also use a swap file. Some programs, like g++, can use huge amounts of virtual memory, requiring the temporary creation of extra space. To install an extra 64 MB of swap space, for example, use the following shell commands:
# dd if=/dev/zero of=/swap bs=1024 count=65535                              
# mkswap /swap
# swapon /swap

The count= argument to dd determines how big the swap file will be. In this example the swap file's name is /swap, but the name and location are, generally, arbitrary, depending only on the file system's available space and your having write permissions in the directory.

When you don't need the swap space any more, remove it with the following statements:

# swapoff /swap                                                             
# rm /swap

Take a look also at the Installation HOWTO and Installation & Getting Started for detailed instructions.

If that still doesn't provide enough swap space, refer to How To Have More Than 128Mb of Swap.

Thursday, December 6, 2007

Why Isn't My Virtual Memory Swap Area Working?

This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).

When you boot (or enable swapping manually) you should see Adding Swap: NNNNk swap-space If you don't see any messages at all you are probably missingswapon -av(the command to enable swapping) in your /etc/rc.local or /etc/rc.d/* (the system startup scripts), or have forgotten to make the right entry in /etc/ fstab:/dev/hda2 none swap sw

for example.
If you see:Unable to find swap-space signature you have forgotten to run mkswap. See the manual page for details; it works much like mkfs.
Running the command free, in addition to showing free memory, should display:
total used free Swap: 10188 2960 7228
If typing cat /proc/swaps reveals only file or partition names, but no swap space information, then the swap file or partition needs re-initialization.Use fdisk (as root) to determine which partition on a hard drive has been designated as the swap partition. The partition still needs to be initialized with mkswap before enabling it with swapon.


Wednesday, December 5, 2007

Where Is the Journalling File System on the Net?

This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).

Linux actually supports several journalling file systems. ext3 is now included in current 2.4.x kernels.A: The journalling file system named Reiserfs has just been released from testing. It is said to make Linux even faster than Linux with the Ext2 file system installed, particularly when dealing with many small files.Complete information is available at http://devlinux.org/namesys/.A: JFS is still under development.

Tuesday, December 4, 2007

How Do I Resize a Partition Non-Destructively?

This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).
A: Use the FIPS.EXE program, included with most Linux distributions,under MS-DOS.

A: GNU parted, a partition editor, is stable enough for non-guru, mere-mortal use with relative confidence. Source code for the latest version is at: ftp:/ /ftp.gnu.org/pub/gnu/parted/. There's also a boot disk image for resizing root partitions and for running parted on non-Linux machines. The disk image may be easier for beginners. Building from source could require some extra configuration.

Parted also has tutorial-style, plain-text documentation for Linux and FAT (MS-DOS) file systems.

A: Also, some commercial distributions come with their own partitioning software, like Partition Magic.

Monday, December 3, 2007

How Do I Create a File System on a Floppy?

This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).
If you are running recent Gnome or KDE desktops, you have a GUI tool that makes formatting floppies easy.

A: To format a 3.5-inch, high density floppy at the command prompt:
$ fdformat /dev/fd0H1440
$ mkfs -t ext2 -m 0 /dev/fd0H1440 1440
For a 5.25 inch floppy, use /dev/fd0h1200 and 1200 as appropriate. For the B: drive use /dev/fd1 instead of /dev/fd0.

The -m 0 option tells mkfs.ext2 not to reserve any space on the disk for the superuserusually the last 10% is reserved for root.The first command performs a low-level format. The second creates an empty file system. You can mount the floppy like a hard disk partition and simply cp and mv files, etc.Device naming conventions generally are the same as for other unices. They can be found in Matt Welsh's Installation and Getting Started guide. Refer to Where Is the Documentation?. A more detailed and technical description is Linux Allocated Devices by H. Peter Anvin, hpa@zytor.com, which is included in LaTeX and ASCII form in the kernel source distribution (probably in /usr/ src/kernel/Documentation/), as devices.tex and devices.txt.

Saturday, December 1, 2007

Can Linux Access MacIntosh File Systems?

This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).
There is a set of user-level programs that read and write the older Macintosh Hierarchical File System (HFS). It is available at metalab.unc.edu/ pub/Linux/utils/disk-management/.Access to the newer, HFS+ file systems is still under development.

Thursday, November 29, 2007

Can Linux Access Amiga File Systems?

This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).
The Linux kernel has support for the Amiga Fast File System (AFFS) version 1.3 and later, both as a compile-time option and as a module. The file Documentation/filesystems/affs.txt in the Linux kernel source distribution has more information.See How To Upgrade/Recompile a Kernel.Linux supports AFFS hard-drive partitions only. Floppy access is not supported due to incompatibilities between Amiga floppy controllers and PC and workstation controllers. The AFFS driver can also mount disk partitions used by the Un*x Amiga Emulator, by Bernd Schmidt.

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