DOS Wedge
Encyclopedia
The DOS Wedge was a popular piece of Commodore 64
system software
. Written by Bob Fairbairn, it was included by Commodore
(CBM) on the 1541 disk drive
Test/Demo Disk (filename: "DOS 5.1") and also packaged with the C64 Macro Assembler (filename: "DOS WEDGE64"). The DOS Wedge was referred to in the 1541 drive manual as DOS Support and on the software startup screen as DOS MANAGER.
The Wedge made disk operations
in BASIC 2.0
significantly easier by introducing several keyword shortcuts. The DOS Wedge became somewhat of a de facto
standard, with third party vendors such as Epyx
often incorporating identical commands into fastloader cartridges and other Commodore 64 expansion devices. COMPUTE!'s Gazette
published several type-in
variations on the DOS Wedge, including a C128
version in its February 1987 issue (see External links, below).
The original Commodore DOS Wedge was a 1-KB
program written in MOS 6502
assembly language
. It resided in the otherwise unused memory block $
CC00–$CFFF (52224–53247) and worked by altering BASIC's "CHRGET" subroutine
at $0073 (115) so that each character passing by the BASIC interpreter would be checked for wedge commands, and the associated "wedged-in" routines run if needed.
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
system software
System software
System software is computer software designed to operate the computer hardware and to provide a platform for running application software.The most basic types of system software are:...
. Written by Bob Fairbairn, it was included by Commodore
Commodore International
Commodore is the commonly used name for Commodore Business Machines , the U.S.-based home computer manufacturer and electronics manufacturer headquartered in West Chester, Pennsylvania, which also housed Commodore's corporate parent company, Commodore International Limited...
(CBM) on the 1541 disk drive
Commodore 1541
The Commodore 1541 , made by Commodore International, was the best-known floppy disk drive for the Commodore 64 home computer. The 1541 was a single-sided 170 kilobyte drive for 5¼" disks...
Test/Demo Disk (filename: "DOS 5.1") and also packaged with the C64 Macro Assembler (filename: "DOS WEDGE64"). The DOS Wedge was referred to in the 1541 drive manual as DOS Support and on the software startup screen as DOS MANAGER.
The Wedge made disk operations
Commodore DOS
Commodore DOS, aka CBM DOS, was the disk operating system used with Commodore's 8-bit computers. Unlike most other DOS systems before or since—which are booted from disk into the main computer's own RAM at startup, and executed there—CBM DOS was executed internally in the drive: the DOS...
in BASIC 2.0
Commodore BASIC
Commodore BASIC, also known as PET BASIC, is the dialect of the BASIC programming language used in Commodore International's 8-bit home computer line, stretching from the PET of 1977 to the C128 of 1985...
significantly easier by introducing several keyword shortcuts. The DOS Wedge became somewhat of a de facto
De facto
De facto is a Latin expression that means "concerning fact." In law, it often means "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established." It is commonly used in contrast to de jure when referring to matters of law, governance, or...
standard, with third party vendors such as Epyx
Epyx
Epyx, Inc. was a video game developer and publisher in the late 1970s and throughout the 1980s. The company was founded as Automated Simulations by Jim Connelley and Jon Freeman, originally using Epyx as a brand name for action-oriented games before renaming the company to match in 1983...
often incorporating identical commands into fastloader cartridges and other Commodore 64 expansion devices. COMPUTE!'s Gazette
COMPUTE!'s Gazette
COMPUTE!'s Gazette was a computer magazine of the 1980s, directed at users of Commodore's 8-bit home computers. Publishing its first issue in July 1983, the Gazette was a Commodore-only daughter magazine of the computer hobbyist magazine COMPUTE!....
published several type-in
Type-in program
A type-in program, or just type-in, is a computer program listing printed in a computer magazine or book, meant to be typed in by the reader in order to run the program on a computer....
variations on the DOS Wedge, including a C128
Commodore 128
The Commodore 128 home/personal computer was the last 8-bit machine commercially released by Commodore Business Machines...
version in its February 1987 issue (see External links, below).
The original Commodore DOS Wedge was a 1-KB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
program written in MOS 6502
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
assembly language
Assembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
. It resided in the otherwise unused memory block $
Hexadecimal
In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
CC00–$CFFF (52224–53247) and worked by altering BASIC's "CHRGET" subroutine
Subroutine
In computer science, a subroutine is a portion of code within a larger program that performs a specific task and is relatively independent of the remaining code....
at $0073 (115) so that each character passing by the BASIC interpreter would be checked for wedge commands, and the associated "wedged-in" routines run if needed.
DOS Wedge functions
Any command that contains an @ symbol may substitute > instead, if desired.- /filename – Load a BASIC program into RAM
- %filename – Load a machine language program into RAM
- ↑filename – Load a BASIC program into RAM and then automatically run it
- ←filename – Save a BASIC program to disk
- @ – Display (and clear) the disk drive status
- @$ – Display the disk directory without overwriting the BASIC program in memory
- @command – Execute a disk drive command (e.g. S0:filename, V0:, I0:)
- @Q – Deactivate the DOS Wedge
External links
- Commodore DOS Wedges: An Overview - Jim ButterfieldJim Butterfield-External links:* * featuring Brad Templeton, Jim Butterfield, and Steve Punter** * * , previous unpublished, presented by the Personal Computer Museum, Brantford, Ontario...
, COMPUTE!COMPUTE!Compute! was an American computer magazine that was published from 1979 to 1994, though it can trace its origin to 1978 in Len Lindsay's PET Gazette, one of the first magazines for the Commodore PET computer. In its 1980s heyday Compute! covered all major platforms, and several single-platform...
, October 1983.
