Popular CPU chips
80286 intel 16 Mediocre CISC
80386 intel 32 Mediocre CISC
80486 intel 32 Fast CISC
Pentium intel 32/64 Really Fast CISC
860 intel 32 Fast RISC
68020 Motorola 32 Mediocre CISC
68030 Motorola 32 Fast CISC
68040 Motorola 32 Faster CISC
88000 Motorola 32 Faster RISC
88100 Motorola 32 Even Faster RISC
R2000 MIPS 32 Fast RISC
R3000 MIPS 32 Faster RISC
R4000 MIPS 32 Really Fast RISC
Microvax DEC 32 Varies CISC
Alpha DEC 64 Extremely Fast RISC
Precision HP 32/64 Extremely Fast RISC
RT PC IBM 32 Mediocre RISC
RS/6000 IBM 32 Fast RISC
SPARC Sun/Others 32 Mediocre to Fast RISC
CISC = Complex Instruction Set Computer - old & slow.
RISC = Reduced Instruction Set Computer - new and fast.
16 bit machines can address 65,536 bytes of memory.
32 bit machines can address 4,294,967,296 bytes of memory.
UNIX used to run in 50k of memory
UNIX now needs about 2MB of memory.
UNIX workstations usually have about 100MB of RAM.
UNIX hosts can have up to 1000MB of RAM.
PCs usually have a maximum of 4 to 8MB of RAM.
UNIX uses virtual memory. Programs are divided into 4k pages. Only the most recently used pages are kept in RAM. If a part of a program is called which is not currently in RAM, it is loaded into a spare page and then executed. It can make programs a lot slower than if they can be fully accommodated in RAM all at once.
Minifloppy rw 5¼" 300k to 1.2M
Microfloppy rw 3½" 400k to 4M
CD-ROM r- 5¼" 600M
Magneto-optical rw 5¼" 600M or more
Tapes rw -- 20MB to 2GB
"Blue Suede Shoes" requires a 5M digital audio file.
A 32-bit machine can directly address 7 CDs-worth of data.
SCSI (scuzzy) Disk/tape drive interface standard.
© 1998 Robert John Morton