The physical memory is divided into pages. The size of a memory page is denned by the
PAGE_SIZE macro in the asm/page.h file. For the x86 processor, the size is set to 4 Kbytes,
while the Alpha processor uses 8 Kbytes.
From : Linux Kernel Internals, Addison WESLEY
NFS Sun’s Network Filesystem (NFS) is the preferred method of file sharing for networks of Unix or Linux computers. The Linux kernel includes both NFS client support
Coda This is an advanced network filesystem that supports features omitted from NFS. These features include better security (including encryption) and improved caching.
SMB/CIFS The Server Message Block (SMB) protocol, which has been renamed the Core Internet Filesystem (CIFS), is the usual means of network file sharing among Microsoft OSs. The Linux kernel includes SMB/CIFS client support, so you can mount SMB/CIFS shares. You can configure your Linux computer as an SMB/CIFS server using the Samba package (http://www.samba.org). The filesystem type code for SMB/CIFS shares is smbfs.
NCP The NetWare Core Protocol (NCP) is NetWare’s file sharing protocol. As with SMB/CIFS, Linux includes basic NCP client support in the kernel, and you can add separate server packages to turn Linux into an NCP server. NCP’s filesystem type code is ncpfs.
BeFS BeOS uses its own journaling filesystem, known as BeFS. A read-only Linux driver for this filesystem
FFS/UFS The Fast Filesystem (FFS; aka Unix Filesystem or UFS) was developed early in the history of Unix. It’s still used by many Unix and derivative systems, including FreeBSD and Solaris. In principle, FFS/UFS could have been adopted as a native Linux filesystem, but Linux’s write support for this filesystem is still considered dangerous
UDF The Universal Disk Format (UDF) is a filesystem designed for recordable CD, DVD, and recordable DVD media. Linux includes UDF support in the 2.4.x kernel series, but the write support is marked ”dangerous” and is very limited in terms of supported hardware.
MFS The Macintosh Filesystem (MFS) was used by the earliest Macintoshes. It’s almost never used on anything but 400KB floppy disks, which are extremely rare today. Linux does not include MFS support.
HFS The Hierarchical Filesystem (HFS) was the replacement for MFS. Used on 800KB and larger floppy disks and all Macintosh hard disks until 1998, HFS is quite common in the Macintosh world.
| HFS+ The follow-on to HFS borrows many features from Unix-style filesystems, but it stops short of adding a journal. New Macintoshes invariably ship with their disks formatted for HFS+, but this filesystem is not used much on removable media. |
FFS MacOS X provides the option to use the Unix Fast Filesystem (FFS), which is described in the next section. Many MacOS X systems continue to use HFS+, though.
chmod
chmod [options] mode(s) filename(s) chmod [options] octal_mode(s) filename(s)
The chmod command is used to change the access mode of files. Only the owner of the file or the superuser may alter its access. There are two methods for expressing the mode you wish to assign. The first is the symbolic method, wherein you specify letters representing the mode. This requires that you specify the following information.
Who is affected:
| u | User who owns the file |
| g | Group (only users in file’s group) |
| o | Other users |
| a | All (default) |
What operation:
| + | Add permission |
| – | Remove permission |
| = | Set permission, overwriting old permissions |
What kind of permission:
| r | Read |
| w | Write |
| x | Execute |
| s | User or group ID is temporarily replaced with that of the file |
| t | Set sticky bit: keep executable in memory after exit |
| File | Contents |
| /proc/interrupts | IRQ information |
| /proc/cpuinfo | CPU information |
| /proc/dma | DMA information |
| /proc/ioports | I/O information |
| /proc/meminfo | Available, free, swap, and cached memory information |
| /proc/loadavg | System load average |
| /proc/uptime | Time since last reboot |
| /proc/version | Information about kernel version |
| /proc/scsi | Information about SCSI devices |
| /proc/ide | Information about IDE devices |
| /proc/net | Network information |
| /proc/sys | Kernel configuration parameters |
| Tool | Requirements | Description |
|---|---|---|
| e2fsck | Included in tomsrtbt-1.6.335 | Checks an ext2 filesystem for errors |
| format | Included with Windows 95 and Windows 98 | Creates a vfat filesystem on a chosen partition |
| mke2fs | Included in tomsrtbt-1.6.335 | Creates an ext2 filesystem on a chosen partition. |
| mkswap | Included in tomsrtbt-1.6.335 | Creates a swap filesystem on a chosen partition. |