Tandy TRS-80 Model IV

TRS-80 was Tandy Corporation's desktop microcomputer model line, sold through Tandy's Radio Shack stores in the late 1970s and early 1980s

The successor to the Model III was the Model 4 (April 1983, with "4" written as an Arabic numeral), which included the capability to run CP/M.

Running CP/M had previously only been possible via a hardware modification that remapped the BASIC ROMs away from memory address zero, such as the third-party add-on sold as the Omikron Mapper board, or by running a version of CP/M modified to run at a starting address other than zero. However, this also required modified applications, since the area of memory at zero contained the vectors for applications to access CP/M itself. The Model 4 also added an 80 column by 24 line video display mode required for CP/M compatibility.

The Model 4 shipped with TRSDOS 6, an enhanced version of LDOS by Logical Systems and a vastly superior operating system to Tandy's earlier TRSDOS offerings. When the Model 4 booted into TRSDOS 6 the video display switched into 80×24 mode and the entire 64KB address space was mapped as RAM. The Model 4 was also capable of running all Model 3 software when a Model 3 operating system disk was detected and loaded during bootup with a 64×16 video mode and Model 3 ROMs mapped from address zero.

The Model 4 also had the ability to display 640×240 or 512×192 high-resolution monochrome graphics with an optional board. A "luggable" version known as the Model 4P (1983) was a self-contained unit with a case design similar to that of a portable sewing machine.

Early versions of the Model 4 mainboard were designed to accept a Zilog Z8000 16 bit CPU upgrade board to replace the Z80 8 bit CPU but this option was never released.

ORIGIN   U.S.A.
YEAR   1983
KEYBOARD   Typewriter style 83 keys with numeric keypad
CPU   Zilog Z80
SPEED   4 MHz
RAM   64 KB (up to 128 KB)
ROM   14 KB
TEXT MODES   64 x 16 / 32 x 16 / 64 x 40 / 80 x 24
GRAPHIC MODES   None
DISPLAY   Monochrome green phosphore
SOUND   Built-in speaker
SIZE / WEIGHT   47.5 (W) x 52 (D) x 31 (H) cm
I/O PORTS   Tape (500 or 1500 bauds), Centronics, I/O ports compatible with Model III, Serial (4D)
OS   TRSDOS 6.0 or 1.3, LDOS, CP/M
POWER SUPPLY   Built-in power supply unit
PRICE   From $1990. In later years the price came down to about $1000
By 1990 the Model 4D was being closed out at $599

Our Model IV was very kindly donated by Edward Gladstone together with his vast coillection of Tandy hardware, software and manuals

Manufacturer: Tandy
Date: 1983

Tandy TRS-80 Model IV Manuals:

Item Manufacturer Date
TRS-80 Colour Graphic Printer Manual Radio Shack
TRS Model I conversion for TRS-80 Radio Shack August 1980
TRS-80 Model I/III Series 1 Editor Assembler Radio Shack 1981
TRS-80 Model 100 Portable Computer Owners Manual Radio shack 1983
Tandy TRS-80 Model 100 Quick Reference Guide Tandy 1983

Magazines RELATED to Tandy TRS-80 Model IV in our Library

Item Manufacturer Date
REM 80 - Volume 3, Issue 4 The North West TRS-80 USers Group
REM 80 - Volume 4, Issue 2 The North West TRS-80 USers Group
REM 80 - Volume 4, Issue 4 The North West TRS-80 USers Group
REM 80 - Volume 5, Issue 2 The North West TRS-80 USers Group
REM 80 - Volume 5, Issue 3 The North West TRS-80 USers Group
REM 80 - Volume 5, Issue 4 The North West TRS-80 USers Group
REM 80 - Volume 6, Issue 5 The North West TRS-80 USers Group
REM 80 - Volume 7, Issue 1 The North West TRS-80 USers Group
REM 80 - Volume 8, Issue 4 The North West TRS-80 USers Group
REM 80 - Volume 9, Issue 4/5 The North West TRS-80 USers Group
REM 80 - Volume 8, Issue 3 The North West TRS-80 USers Group
REM 80 - Volume 11, Issue 1 The North West TRS-80 USers Group
REM 80 - Volume 6, Issue 1 The North West TRS-80 USers Group
REM 80 - Volume 7, Issue 4 The North West TRS-80 USers Group
REM 80 - Volume 9, Issue 6 The North West TRS-80 USers Group
REM 80 - Volume 6, Issue 3 The North West TRS-80 USers Group
REM 80 - Volume 9, Issue 1 The North West TRS-80 USers Group
REM 80 - Volume 9, Issue 2 The North West TRS-80 USers Group
Popular Electronics - October 1977 October 1977
Personal Computer World - August 1978 August 1978
Personal Computer World - September 1978 September 1978
Practical Computing - October 1978 October 1978
Personal Computer World - October 1978 October 1978
Practical Computing - November 1978 November 1978
Practical Computing - December 1978 December 1978
TRS--80 Computing Volume 1 Number 1 Radio Shack - Tandy 1979
Practical Computing - August 1979 August 1979
Practical Computing - November 1979 November 1979
Practical Computing - January 1980 January 1980
Personal Computer World - June 1980 June 1980
REM 80 - Volume 3, Issue 1 The North West TRS-80 USers Group 1981
REM 80 - Volume 3, Issue 3 The North West TRS-80 USers Group 1981
Personal Computer World - July 1981 July 1981
Personal Computer World - September 1981 September 1981
Your Computer - December 1981 December 1981
TRS-80 Microcomputer News Volume 1 Number 1 Radio Shack - Tandy January 1982
TRS-80 Microcomputer News Volume 1 Number 2 Radio Shack - Tandy February 1982
Personal Computer World - May 1982 May 1982
Personal Computer World - December 1982 December 1982
REM 80 - Volume 5, Issue 5 The North West TRS-80 USers Group 1983
REM 80 - Volume 5, Issue 6 The North West TRS-80 USers Group 1983
REM 80 - Volume 6, Issue 2 The North West TRS-80 USers Group 1983
Practical Computing - April 1983 April 1983
Personal Computer World - August 1983 August 1983
TRS-80 Microcomputer News October 1983 October 1983
Practical Computing - October 1983 October 1983
Call-A.P.P.L.E. - November 1983 November 1983
REM 80 - Volume 7, Issue 2 The North West TRS-80 USers Group 1984
REM 80 - Volume 6, Issue 4 The North West TRS-80 USers Group 1984
Personal Computer World - February 1984 February 1984
Personal Computer World - May 1984 May 1984
Byte May 1984 May 1984
Personal Computer World - August 1984 August 1984
Byte March 1984 October 1984
REM 80 - Volume 7, Issue 5 The North West TRS-80 USers Group 1985
REM 80 - Volume 8, Issue 1/2 The North West TRS-80 USers Group 1986
Practical Computing - April 1980 25-08-2009
Practical Computing - January 1981 09-09-2009

Other Systems Related To Tandy TRS-80 Model IV:

Item Manufacturer Date
TRS-80 Microcomputer System Model 1 Level 1 Radio Shack - Tandy 1977
TRS-80 Color Computer Tandy 1980
TRS-80 Model 100 Portable Computer Tandy Radio Shack 1983
TRS-80 Model 102 Portable Computer Tandy Radio Shack 1983
Tandy 102 Portable Computer Tandy Radio Shack 1983
TRS-80 Colour Computer 2 Radio Shack Tandy 1983
Tandy 1000 EX Personal Computer Tandy December 1986
Tandy 1000 HX Personal Computer Tandy 1987
Tandy 1100FD Laptop Computer Tandy Radio Shack November 1989

This exhibit has a reference ID of CH15780. Please quote this reference ID in any communication with the Centre for Computing History.

 

Tandy TRS-80 Model IV

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  Software Archive   [19]
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