Glossary

Hardware

AHA-1542 - name of the most common Adaptec SCSI controller

BIOS - code in ROM that initializes a peripheral card

ISA bus - bus connecting the processor to the peripheral card

SCSI bus -bus connecting the controller card to the tape drive

QIC - Quarter Inch Cartridge industry specifications

address - location on a bus

dma - direct memory access

ftpi - flux transitions per inch

io - input/output

irq - interrupt request line

Operating System

ANSI - standards organization responsible for the C language and many of the conventions used by tdcback

GMT - Greenwich Mean Time

I/O manager - server that provides access to controller hardware

blocked - state of program execution in which a program is not scheduled to run

client - program that requests services from another

directory - file system construct that groups files and maintains date, ownership, and status information

directory tree -directories related by a common hierarchy

extents - file system construct that allows large files to be assembled from discontiguous blocks

file - smallest unit of storage available to a user from the filesystem

group - eight bit number used to identify users who belong in the same security class

user - eight bit number used to identify users

path - collection of directories in a file's hierarchy

permissions - security system for files and devices that prevents unauthorized users from accessing protected files and prevents owners of files from performing unathorized operations on files

prefix - root slash in a filename, i.e. / 

proxy - software abstraction of an irq

process - program that has been loaded into memory

server - program that supplies information to clients

stderr - character stream for error messages

stdin - character stream for user input

stdout - character stream for program output

superuser - user whose group and user values are both 0

volume - group of related files on a backup medium

Shell

background - program execution in which the shell returns a prompt to the user before the current program has completed

prompt - short message displayed by the shell to inform a user that input is needed

redirect - assignment of stdin, stdout, or stderr to streams other than the console

shell - program that allows human interaction with the operating system

> - shell command line symbol for stdout

< - shell command line symbol for stdin

2> - shell command line symbol for stderr

| - shell command line symbol for equating the stdout stream of the program on the left of the symbol with the stdin stream of the program on the right of the symbol

<Enter> - symbol used to indicate the user should press enter key

# - shell prompt for superusers

$ - shell prompt for regular users

& - shell command line symbol for background execution

\ - pattern matching symbol that forces then next symbol to be interpreted as a regular character

\\ - symbol in shell scripts that passes \ to a sub command, the first \ is parsed by the shell, the second is passed to the command

* - pattern matching symbol that matches any run of characters

? - pattern matching symbol that matches any single character

[ ] - pattern matching symbols used to enclose a list of characters, each of which will produce a positive match

^ - pattern matching symbol used to negate the meaning of a match

^d - character formed by pressing the control, 'Ctrl', and the 'D' keys, indicates the end of a user input stream

! - symbol used in secondcopy's pattern matching that, when entered as the first character of a pattern, causes secondcopy to negate the meaning of the pattern, files matching the pattern will be skipped

Supplied Programs

backup.s - a shell script showing a complete backup example

sc - utility program supplied in this package

secondcopy - tape backup program in this package

scdir - utility for directories supplied in this package

Other Programs

badblock - program that determines the integrity of disk blocks

cat - program that copies stdin to stdout

chmod - program that changes the permissions of files

chown - program that changes the owner of files

cron - program that starts other programs at a predetermined time

echo - program that copies its command line to stdout

fdformat - program that prepares a floppy for use

fdisk - program that initializes the partitions on a hard disk

find - program that traverses a directory tree and reports on the files in the tree

ls - program that displays information about files

mkdir - program that makes a directory

mkfs - program that creates a Linux file system on disk

ps - program for reporting system information, including process states

tar - program for making backups