...devices.
See mknod(1,2) for an explanation of how to make these files.

...numbers.
This is not strictly true, but is close enough. If you understand where it is not true, you don't need to read this section, and if you don't but want to learn, read the code for the tty devices, which uses up 2 major numbers, and may use a third and possibly fourth by the time you read this.

.../dev/mouse.
Even though XFree86 is now able to read PS/2 style ``droppings'', the concepts in this example still stand. If you have a better example, I'd be glad to see it.

...register_chrdev().
See sectiongif

...details.
Although SCSI disks and CDROMs are block devices, SCSI tapes, like other tapes, are generally used as character devices.

...disk.
A used 20 MB MFM hard disk and controller should cost less than US$100.

...helpful.
The October 17, 1991, draft of the SCSI-2 standard document is available via anonymous ftp from sunsite.unc.edu in /pub/Linux/development/scsi-2.tar.Z, and is available for purchase from Global Engineering Documents (2805 McGaw, Irvine, CA 92714), (800)-854-7179 or (714)-261-1455. Please refer to document X3.131-199X. In early 1993, the manual cost US$60--70.

...interrupt-driven,
Some of the early drivers were not interrupt driven and, consequently, had very poor performance.

...interleave,
``1:1 interleave'' means that all of the sectors in a single track appear consecutively on the disk surface.

...sectors.
This may be an over-simplification. On older devices, the actual command processing can be significant. Further, there is a great deal of layered overhead in the kernel: the high-level SCSI code, the buffering code, and the file-system code all contribute to poor SCSI performance.

...bus
The so-called ``Industry Standard Architecture'' bus was introduced with the IBM PC/XT and IBM PC/AT computers.

...bus
The ``Extended Industry Standard Architecture'' bus is a non-proprietary 32-bit bus for 386 and i486 machines.

...bus
The ``Micro-Channel Architecture'' bus is IBM's proprietary 32 bit bus for 386 and i486 machines.

...code
0.99.7 kernel source code, linux/kernel/irq.c

...declaration
0.99.5 kernel source code, linux/kernel/irq.c

...definition
0.99.5 kernel source code, linux/include/linux/signal.h

...#figcommand#1367>.
0.99.5 kernel, linux/kernel/blk_drv/scsi/aha1542.c, written by Tommy Thorn.

...MS-DOS
MS-DOS is a registered trademark of Microsoft Corporation.

...structure,
0.99.7 kernel, linux/kernel/blk_drv/scsi/scsi.h

...are,
Usually a file called a namelist file, often /etc/psdatabase.

...steps:
Unless you are making a subdirectory of the replicating, dynamically allocated process directory, you would have to create a new filesystem type, similar to the proc filesystem in design. Subdirectories of the process directories are supported by the mechanism which dynamically creates the process directories. I suggest going through this explanation of how to add a non-dynamically-allocated directory, understand it, and then read the code for the process subdirectories, if you wish to add subdirectories to the process subdirectories.

...model:
This file is available as file proc/foo.c in the The Linux Kernel Hackers' Guide source mentioned on the copyright page.

...addresses
In the 80386, linear address run from 0GB to 4GB. A linear address points to a particular memory location within this space. A linear address is not a physical address --- it is a virtual address.

...addresses
A logical address consists of a selector and an offset. The selector points to a segment and the offset tells how far into that segment the address is located.

...task
Sometimes called the swapper task, even though it has nothing to do with swapping in the \ implementation, for historical reasons

Ross Biro
Mon May 22 11:57:09 PDT 1995