TR-DOS

---

title: "TR-DOS" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["microcomputer-software", "zx-spectrum", "disk-operating-systems"] description: "Disk operating system for the ZX Spectrum" topic_path: "technology/operating-systems" source: "https://en.wikipedia.org/wiki/TR-DOS" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Disk operating system for the ZX Spectrum ::

::data[format=table title="Infobox OS"]

Field	Value
name	TR-DOS
logo
screenshot
version of
developer	Technology Research Ltd
family
working state
source model
released
discontinued
RTM date
GA date
latest release version	5.03
latest release date
latest preview date
language	English
update model
package manager
supported platforms	ZX Spectrum
kernel type
license	proprietary
website
support status
::

| name = TR-DOS | logo = | logo caption = | logo size = | logo alt = | screenshot = | caption = | screenshot_size = | screenshot_alt = | collapsible = | version of = | developer = Technology Research Ltd | family = | working state = | source model = | released = | discontinued = | RTM date = | GA date = | latest release version = 5.03 | latest release date = | latest preview version = | latest preview date = | marketing target = | programmed in = | language = English | update model = | package manager = | supported platforms = ZX Spectrum | kernel type = | userland = | ui = | license = proprietary | preceded by = | succeeded by = | website = | support status = | other articles = | prog_language = TR-DOS is a disk operating system for the ZX Spectrum with Beta Disc and Beta 128 disc interfaces. TR-DOS and Beta disc were developed by Technology Research Ltd (UK), in 1984. A clone of this interface is also used in the Russian Pentagon and Scorpion machines.

It became a standard in Russia and most disk releases for the ZX Spectrum, especially of modern programs, are made for TR-DOS as opposed to other disk systems.

The latest official firmware version is 5.03 (1986). Unofficial versions with various enhancements and bug-fixes have been released since 1990, with the latest being 6.10E (2006).

TR-DOS handles SS/DS, SD/DD floppy disks. All modern versions support RAM Disk and some versions support hard disks.

Current emulators support TR-DOS disk images in the formats .TRD or .SCL.

Commands

The following list of commands is supported by TR-DOS V4.

• 40
• CAT
• CLOSE
• [COPY](copy-command)
• [ERASE](del-command)
• [FORMAT](format-command)
• GO TO
• INPUT
• LOAD
• [MOVE](move-command)
• NEW
• OPEN
• PRINT
• RETURN
• RUN
• SAVE

Utility programs include:

• FILER
• TAPECOPY (replaces BACKUP, COPY and SCOPY utility programs in TR-DOS V3)

References

References

1. "Beta Disk Interface - World of Spectrum".
2. Woodcock, Colin. (7 May 2012). "The ZX Spectrum on Your PC". Lulu.com.
3. Woodcock, Colin. (December 2003). "TR-DOS". ZXF.
4. (2022). "Virtual TR-DOS".
5. (1986). "Technology Research BETA 128 Disk Interface - User Manual". Technology Research Ltd.
6. "Customized ROM".
7. (1984). "DISK INTERFACE Manual Supplement for version 4 of TR-DOS". Technology Research Limited.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::