Editing TRSDOS (section)

{{Short description|Operating system for Tandy TRS-80 computers}}
{{Infobox OS
| name                   = TRSDOS
| logo                   = 
| screenshot             = [[File:TRSDOS 6.02.jpg|300px]]
| caption                = Boot Screen of Model 4 TRSDOS 6
| developer              = [[Tandy Corporation|Tandy]]
| source_model           = [[Closed source]], [[Source-available software]]<ref name="the-source" />
| kernel_type            = [[monolithic kernel|Monolithic]]
| supported_platforms    = [[Zilog Z80]]-based [[TRS-80]]s
| ui                     = [[Command-line interface]]
| released               = Model I in {{Start date and age|1977}}
| latest_release_version = Model 4 Version 6.2
| latest_release_date    = {{Start date and age|1984}}
| latest_test_version    = 
| latest_test_date       = 
| marketing_target       = 
| programmed_in          = 
| prog_language          = 
| language               = [[English language|English]]
| updatemodel            = 
| package_manager        = 
| working_state          = Historic
| license                = 
| website                = 
}}
'''TRSDOS''' (which stands for the '''T'''andy '''R'''adio '''S'''hack '''D'''isk '''O'''perating '''S'''ystem) is the [[operating system]] for the [[Tandy TRS-80]] line of eight-bit [[Zilog Z80]] microcomputers that were sold through [[Radio Shack]] from 1977 through 1991. Tandy's manuals recommended that it be pronounced ''triss-doss''. TRSDOS should not be confused with '''Tandy DOS''', a version of [[MS-DOS]] licensed from [[Microsoft]] for Tandy's [[x86]] line of [[personal computer]]s (PCs).

With the original TRS-80 Model I of 1977, TRSDOS was primarily a way of extending the MBASIC ([[BASIC]] in [[read-only memory|ROM]]) with additional [[I/O]] (input/output) commands that worked with disk files rather than the [[cassette tape]]s that were used by non-disk Model I systems. Later disk-equipped [[TRS-80 Model III|Model III]] computers used a completely different version of TRSDOS by Radio Shack which culminated in 1981 with TRSDOS Version 1.3. From 1983 disk-equipped [[TRS-80 Model 4]] computers used TRSDOS Version 6, which was a development of Model III LDOS by Logical Systems, Inc. This last was updated in 1987 and released as LS-DOS 6.3.

Completely unrelated was a version of TRSDOS by Radio Shack for its [[TRS-80 Model II]] professional computer from 1979, also based on the Z80 and equipped with 8-inch disk drives. The later machines in this line, the Models 12, 16 and 6000, used the Z80 as an alternate CPU to its main [[Motorola 68000]] chip and could run this version of TRSDOS for [[backwards compatibility]] with older Z80 applications software.