TRS-DOS

Infobox OS
name = TRS-DOS



caption =
developer = Tandy
source_model =
kernel_type =
supported_platforms = TRS-80
ui = Command line interface
family = DOS
released = late 1970s
latest_release_version = 1.3
latest_release_date = May 1, 1981
latest_test_version =
latest_test_date =
marketing_target =
programmed_in =
prog_language =
language = English
updatemodel =
package_manager =
working_state = Historic
license =
website =

TRS-DOS (which stood for the Tandy Radio Shack - Disk Operating System) was the operating system for the Tandy TRS-80 line of 8-bit Z-80 micro-computers that were sold through Radio Shack through the late 1970s and early 1980s. Their own manuals recommended that it be pronounced "triss-doss" but the common derisive term referred to the platform as "trash-eighties" and thus this software was sometimes called "trash-dos" by loyalists of other computing platforms.fact|date= May 2008 TRS-DOS should not be confused with Tandy DOS a version of MS-DOS licensed from Microsoft for Tandy's x86 line of PC's.

TRS-DOS was primarily a way of extending the MBASIC (BASIC in ROM) with additional I/O (input/output) commands that worked with disk files rather than the cassette tapes that were used by most other TRS-80 systems.

TRS-DOS supported up to four floppy (mini-diskette) drives which used 5 1/4" (five and one quarter inch) diskettes with a capacity of 160K (kilobytes) each. The drives were numbered 0 through 3 and the "system" diskettes (which contained the TRS-DOS code and utilities) had to be in drive 0.

Commands

Some typical TRS-DOS utilities:

:Notes: :* Since TRS-DOS didn't have the notion of "redirection" as UNIX/Linux and MS-DOS do, the APPEND command is somewhat different in concept than the UNIX or MS-DOS notion of appending via output redirection.:* The CLOCK command display a real time clock in the upper corner of the display, almost like a DOS TSR (terminate and stay resident); no exactly corresponding feature exists in MS-DOS or UNIX, though many programs provided similar features for DOS and the common UNIX shells could embed the time into their user defined "prompt string":* program invocation under DOS and UNIX is done by filename; no explicit LOAD command is required for normal binary executables nor for text command files (batch files in DOS and shell scripts in UNIX/Linux).:* Under DOS and UNIX printing a file can be done with redirection; under UNIX it's normally done by spooling the file to the "line printer" (using the "lpr" command) because UNIX is conventionally a multi-user system.:* ATTRIB, PROT, and the "chmod" UNIX command are all somewhat different in their semantics. UNIX/Linux is multi-user and each user can control read, write, and execute permissions on his or her own files and directories. MS-DOS is single user and the file attributes for "read-only," "hidden," and "system" are advisory in nature. TRS-DOS was single user but supported some sort of on disk password protection for specific files.:* The AUTO command set an automatic command to be executed on TRS-DOS boot; under MSDOS the special, reserved file named AUTOEXEC.BAT contained a list of such commands. On UNIX a set of one or more "rc" files under "/etc/" are a set of boot time "run commands" and special "dot files" in a user's home directory are run for each time that a given user logs into the system. UNIX supports many other "dotfiles" for many of its commands which are akin to the Macintosh "preferences" folder contents.:* TRS-DOS (version II) was notable for the inclusion of "noise" words, similar to the 1959 COBOL specification. These made commands more English-like. For example, the following commands functioned identically::**COPY filea fileb:**COPY filea TO fileb:**COPY fileb FROM filea:* Many versions supported a simple password security for files and programs, with separate Read/Execute and full access capabilities. ex: "filename/ext.password:drive#"

Although MS-DOS owes its heritage most closely to CP/M and thence to TOPS-10, many of the file manipulation commands are very similar to those of TRS-DOS. By comparison the CP/M command for copying files was called "pip" (both a pun on the Pip printers, a chain of copy centers in that era, and an acronym standing for "peripheral interface to peripheral").

Dates

* May 8, 1979 - Radio Shack releases TRSDOS 2.3
* May 1, 1981 - Radio Shack releases Model III TRSDOS 1.3

External links

* [http://personal.nbnet.nb.ca/mclays/trsdos.html Mike's Virtual Computer Museum: TRS-80]
* [http://home.iae.nl/users/pb0aia/cm/m2errors.html TRS-80 Error Messages]
* [http://www.trs-80.com/trs80-4n.htm TRS-80 Revived Software Collection] (good pictures of a Model IV)
* [http://www.kjsl.com/trs80/model3info.html Model III Home Page] (with list of TRS-DOS alternatives on the TRS-80 Model III
* [http://www.trs-80emulators.com/ Matthew Reed's TRS-80 Emulator Software] Runs under MS-DOS; requires the extraction of a ROM image
* [http://www.tim-mann.org/xtrs.html xtrs] A TRS-80 emulator for UNIX and X11; similar ROM issues apply
* [http://members.shaw.ca/gp2000/trsdisk/trsdisk.html TRSdisk - TRS-DOS utilities for UNIX]
* [http://pilot.ucdavis.edu/davidk/trs80/software/disk_app_page.htm TRS-DOS Applications]