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Unix V4 Software Catalog

Unix V4 Software Catalog

Table of Contents

System Information

# There is no uname in Unix V4 - it was introduced in Unix V7 (1979)
# System identification must be done manually:

# cat /usr/sys/ken/main.c | head -5
/*
 *	Copyright 1973 Bell Telephone Laboratories Inc
 */

# Memory and process info:
# ps
  PID TTY TIME CMD
    1     0:03 /etc/init
   13 8   0:00 -
   14 8   0:00 ps

Filesystem Layout

/           Root filesystem
├── bin/    Core utilities (49 commands)
├── dev/    Device files
├── etc/    System configuration
├── lib/    Libraries (libc, assembler)
├── mnt/    Mount point
├── tmp/    Temporary files
├── unix    Kernel binary
└── usr/    User programs and source
    ├── bin/     Additional utilities (~40 commands)
    ├── c/       C compiler source
    ├── games/   Entertainment (7 games)
    ├── lib/     User libraries
    ├── source/  System source
    └── sys/     Kernel source
        ├── ken/     Ken Thompson's code
        └── dmr/     Dennis Ritchie's code

/bin - Core Utilities (49 commands)

Command Size Description
ar 2,058 Archive maintainer (create/modify .a files)
as 21,334 PDP-11 assembler
bas 7,074 BASIC interpreter
cat 330 Concatenate and print files
cc 4,302 C compiler driver
cdb 3,928 C debugger
check 1,454 Filesystem consistency check
chmod 666 Change file mode
chown 468 Change file owner
clri 330 Clear inode
cmp 502 Compare two files
cp 546 Copy files
date 1,164 Print or set date/time
db 5,018 Debugger
dc 3,430 Desk calculator (arbitrary precision)
dd 1,730 Convert and copy files
df 656 Disk free space
dsw 628 Delete interactively
du 822 Disk usage summary
dump 2,816 Filesystem backup
echo 216 Echo arguments
ed 6,854 Line editor
exit 72 Exit shell
fc 1,214 Fortran compiler (front end)
goto 422 Shell goto for scripts
if 694 Conditional command
kill 302 Send signal to process
ld 6,194 Link editor (linker)
ln 324 Make links
login 1,076 Login program
lpr 1,052 Line printer spooler
ls 1,506 List directory contents
mail 2,406 Send/receive mail
mkdir 226 Make directory
mv 786 Move files
nm 1,430 Print symbol table
od 1,066 Octal dump
pr 1,876 Print files with pagination
ps 2,150 Process status
restor 2,528 Restore from dump
rew 208 Rewind tape
rm 600 Remove files
rmdir 194 Remove directory
sh 6,314 Bourne shell (Thompson shell)
size 608 Print section sizes of binary
sort 4,006 Sort lines
strip 866 Remove symbol table
stty 890 Set terminal options
su 500 Substitute user (become root)
sum 330 Checksum a file
sync 98 Flush filesystem buffers
time 340 Time a command
tp 3,668 Tape manipulator (tar ancestor)
tty 194 Print terminal name
uniq 874 Report repeated lines
who 604 Who is logged in
write 1,000 Write to another user

Command Categories

Text Processing

  • cat - display files
  • cmp - compare files
  • echo - echo text
  • ed - line editor (THE editor of Unix)
  • pr - paginate for printing
  • sort - sort lines
  • uniq - unique lines

File Management

  • cp - copy
  • ln - link
  • ls - list
  • mkdir - make directory
  • mv - move/rename
  • rm - remove
  • rmdir - remove directory

Development Tools

  • ar - archive maintainer
  • as - assembler
  • cc - C compiler
  • cdb - C debugger
  • db - debugger
  • fc - Fortran compiler
  • ld - linker
  • nm - symbol table
  • size - section sizes
  • strip - remove symbols

System Administration

  • check - filesystem check
  • chmod - change mode
  • chown - change owner
  • clri - clear inode
  • df - disk free
  • du - disk usage
  • dump - backup
  • restor - restore
  • sync - flush buffers

Process Control

  • kill - send signal
  • ps - process status
  • time - time command

Communication

  • mail - electronic mail
  • who - users logged in
  • write - send message

Other

  • bas - BASIC interpreter
  • date - date/time
  • dc - desk calculator
  • dd - convert/copy
  • login - login
  • sh - shell
  • su - substitute user

/usr/bin - User Utilities (~40 commands)

Command Description
adb Advanced debugger
arcv Archive converter
bc Calculator language (uses dc)
col Filter reverse line-feeds
comm Common lines in sorted files
cref Cross reference
diff File differences
file Determine file type
find Find files
grep Search for patterns
lex Lexical analyzer generator
look Find lines in sorted file
mesg Permit/deny messages
nroff Text formatter
passwd Change password
pfe Print floating exception
prof Execution profiler
ptx Permuted index
rev Reverse lines
roff Text formatter
sa Shell accounting
salloc String allocation
speak Word pronunciation
split Split files
su Substitute user
sum Checksum
tabs Set terminal tabs
tc TROFF typesetter interface
tr Translate characters
troff Typeset formatter
typo Find typos
wc Word count
yacc Parser generator (Yet Another Compiler Compiler)

Notable Utilities

grep - Global Regular Expression Print

First appearance of the legendary pattern matcher: 

# grep 'main' /usr/sys/ken/*.c
main.c:main()

yacc - Parser Generator

Stephen C. Johnson's compiler-compiler, still used today: 

# ls /usr/lib/yaccpar
/usr/lib/yaccpar

diff - File Comparison

Douglas McIlroy's diff algorithm: 

# diff file1 file2
3c3
< old line
---
> new line

/usr/games - Entertainment (7 programs)

Game Size Description
bj 1,562 Blackjack card game
chess 14,310 Chess with opening book
cubic 2,468 4x4x4 3D tic-tac-toe
moo 624 Bulls and Cows (Mastermind precursor)
ttt 2,192 Tic-tac-toe with learning AI
ttt.k 268 TTT knowledge/learning file
wump 5,386 Hunt the Wumpus (cave adventure)

See Unix V4 Games for detailed analysis.

/lib - System Libraries

File Size Description
libc.a 12,856 C runtime library
liba.a 2,460 Assembler library
crt0.o 116 C runtime startup
fr0.o 224 Floating-point runtime
filib.a 2,174 Floating-point library
libf.a 9,792 Fortran library

libc.a Contents

Core C library functions (partial list): 

# ar t /lib/libc.a
crt0.o     - C runtime startup
alloc.o    - memory allocation
atof.o     - ASCII to float
atoi.o     - ASCII to integer
ecvt.o     - float conversion
fltpr.o    - float print
getc.o     - get character
getchar.o  - get char from stdin
ldiv.o     - long division
ltod.o     - long to double
printf.o   - formatted print
putc.o     - put character
putchar.o  - put char to stdout
qsort.o    - quicksort
setjmp.o   - non-local goto

/usr/sys - Kernel Source

/usr/sys/ken - Ken Thompson's Code

File Lines Description
main.c 217 Kernel initialization
slp.c 239 Sleep/wakeup mechanism
prf.c 131 printf for kernel
trap.c 157 Trap/interrupt handling
sig.c 131 Signal handling
sys1.c 235 System calls (exec, exit, wait, fork)
sys2.c 238 System calls (read, write, open, close)
sys3.c 192 System calls (stat, chmod, chown)
sys4.c 147 System calls (time, stime, getuid)
sysent.c 76 System call table
clock.c 78 Clock interrupt handler
fio.c 121 File I/O primitives
iget.c 152 Inode management
alloc.c 155 Block allocation
nami.c 131 Pathname resolution
pipe.c 95 Pipe implementation
rdwri.c 100 Read/write implementation
subr.c 145 Subroutines
text.c 126 Text segment management

/usr/sys/dmr - Dennis Ritchie's Code

File Lines Description
bio.c 265 Block I/O system
tty.c 448 Terminal driver
kl.c 78 KL11 console driver
pc.c 103 PC11 paper tape driver
lp.c 76 LP11 line printer driver
rk.c 98 RK05 disk driver
rf.c 81 RF11 fixed-head disk driver
tc.c 111 TC11 DECtape driver
tm.c 130 TM11 tape drive driver
dc.c 95 DC11 communications driver
dh.c 186 DH11 multiplexer driver
dn.c 60 DN11 autodialer driver
dp.c 168 DP11 driver
mem.c 56 Memory device (/dev/mem)
partab.c 16 Parity table
cat.c 56 Phototypesetter driver
vs.c 63 Voice synthesizer driver

/usr/c - C Compiler Source

File Description
c00.c Compiler pass 0 - lexer
c01.c Compiler pass 0 - parser
c02.c Compiler pass 0 - declarations
c03.c Compiler pass 0 - expressions
c04.c Compiler pass 0 - output
c10.c Compiler pass 1 - code generation
c11.c Compiler pass 1 - expressions
c12.c Compiler pass 1 - statements
c13.c Compiler pass 1 - optimizer
c20.c Compiler pass 2 - peephole optimizer
c21.c Compiler pass 2 - final output
cvopt.c Optimizer tables
table.s Instruction tables (assembler)

The compiler runs in multiple passes to fit in limited memory.

/etc - System Configuration

File Description
init Init process (PID 1)
getty Terminal line setup
glob Filename expansion (/etc/glob pattern)
msh Mini shell for single-user mode
passwd User database
rc Startup script
ttys Terminal configuration
mtab Mounted filesystems

/etc/passwd Format

root::0:1::/:
bin::3:1::/bin:

Fields: name:password:uid:gid:gecos:home:shell

Note: Empty password field means no password required!

/dev - Devices

Device Description
rk0 RK05 disk, raw
rrk0 RK05 disk, block
tty0-8 Terminals
mem Physical memory
kmem Kernel memory
null Null device
mt0 Magnetic tape
lp Line printer

System Calls (41 total)

# Name Description
0 indir Indirect system call
1 exit Terminate process
2 fork Create process
3 read Read from file
4 write Write to file
5 open Open file
6 close Close file
7 wait Wait for child
8 creat Create file
9 link Link to file
10 unlink Remove file
11 exec Execute program
12 chdir Change directory
13 time Get time
14 mknod Make special file
15 chmod Change file mode
16 chown Change owner
17 break Set data segment size
18 stat File status
19 seek Seek in file
20 getpid Get process ID
21 mount Mount filesystem
22 umount Unmount filesystem
23 setuid Set user ID
24 getuid Get user ID
25 stime Set time
26 ptrace Process trace
28 fstat File status by descriptor
31 stty Set terminal
32 gtty Get terminal
34 nice Set priority
35 sleep Sleep
36 sync Sync filesystem
37 kill Send signal
38 switch Get/set switch register
41 dup Duplicate file descriptor
42 pipe Create pipe
43 times Get process times
44 prof Profiling
46 setgid Set group ID
47 getgid Get group ID
48 signal Set signal handler

Statistics Summary

Category Count
/bin commands 49
/usr/bin commands ~40
/usr/games 7
System calls 41
Kernel files ~35

Total: ~100 user commands, plus kernel and libraries.

Historical Notes

What's Missing (added in later versions)

  • vi - Visual editor (BSD, 1976)
  • awk - Pattern language (V7, 1977)
  • sed - Stream editor (V7, 1974/77)
  • make - Build system (V7, 1977)
  • uname - System identification (V7, 1979)
  • more/less - Pagers (BSD)
  • curses - Screen library (BSD)
  • csh - C shell (BSD, 1978)

What's Already There

Remarkably, Unix V4 already had:

  • Complete C development environment
  • grep and other text tools
  • Pipes and redirection
  • Multi-user capability
  • Hierarchical filesystem
  • Device abstraction
  • Process control

All in ~2.5MB of disk space.

References

Author: Jason Walsh

jwalsh@nexus

Last Updated: 2025-12-25 00:01:03

build: 2026-04-17 18:37 | sha: 792b203