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K > KAYPRO > Kaypro 4   

Kaypro 4

This is the Kaypro 4 released in 1984, usually refered as Kaypro 4/84, as opposed to the Kaypro IV released one year earlier, and refered as Kaypro IV '83.

The main differences between the Kaypro 4 '84 and the Kaypro IV '83 were :
- A faster CPU, Zilog Z80A running at 4Mhz,
- A real time clock which can be used by programs (uses National MM58167),
- A better built-in monitor resulting in a very sharp display. The character matrix has also evolved from 5 x 7 on the Kaypro II and IV '83 to 8 x 16 pixels on the Kaypro 4 '84,
- the system had rudimentary graphics through graphical characters resulting in a virtual 160 x 100 resolution,
- characters could be displayed using two brightness levels and reverse attribute,
- the new prompt was a blinking square,
- like on modern keyboards, J and F keys were slightly different in shape from the other keys, so it was possible to spot them while staring at the screen,
- there was a built-in modem (300 baud, Bell System 103 compatibility, uses Texas Instruments TMS99537/TMS99532),
- the system had two DS/DD half-height floppy drives (390 kb)

The system was bundled with Wordstar, dBase II, MicroPlan, Microsoft Basic, S-Basic, SuperCalc, C-Basic and CP/M 2.2 !

In 1984, in order to be compatible with IBM software, a special version was marketed with an Intel 8088 CPU in addition of the Z80A. It was called Kaypro 4 Plus 88!


Walter J. Dickie reports:
The Plus 88 was a dual-processor machine. First you booted up in CP/M, then inserted an MS-DOS (not PC-DOS) disk and booted the 8088. The really slick thing about the Plus was that in CP/M you could run the 8088 and it's associated 256K of RAM as a ramdisk. My standard boot routine involved booting in CP/M, firing up the 8088 as a ramdisk, copying all the WordStar overlay files onto the ramdisk (they just fit), then running WordStar on the Z80. With WordStar calling its overlays from the ramdisk the damn thing just flew!

Please consider donating your old computer / videogame system to or one of our partners from anywhere in the world (Europe, America, Asia, etc.).

Special thanks to Michael Loasby who donated us this computer !


Like Andy M-S, I have a 2/84 which does not seem documented here. It had improved display and the rear looked just like the 2X, but did not have the X and had a "3" sticker just like the 4/84. Place for a fan but no fan installed. It lacked the modem or clock, but had the plug for the modem (inactive). I had 180K drives, not the 4x 360K drives. So somewhere between the 4/84 and 2X. It still runs just fine. I fire it up about every 2-3 months just for fun.

Wednesday 11th January 2017
Robert Pearse (United States)

You never forget your first! A really sweet system. Still works except maybe the Bios Battery needs replacing. Still have all the manuals and disks.

Wednesday 26th February 2014
Charlie (Santa Cruz, CA)

In 1984, I bought a 2/84 machine. By the end of its life (c. 1993) I had upgraded it with DSDD drives, an Advent TurboROM, EZCPR (ZCPR2, for all intents and purposes) and a 256K coprocessor, which (like others) I used primarily as a RAMdisk. My boot disk loaded Perfect Writer''s swap file, along with all of my main utilities, onto the RAM drive, and I then put a "utility" disk into drive A (which via magic was now drive B$the RAM drive was A:) and put my data disk into drive B: (which via magic was then drive C:). That machine was absolutely wonderful, and as heavy and awkward as it could be at times, I really miss it. (Oh, and it fed an Okidata ml92 and an Anderson-Jacobson TTY that I used as a daisy-wheel printer).

Friday 21st February 2014
Andy M-S


NAME  Kaypro 4
TYPE  Transportable
YEAR  1984
KEYBOARD  Detachable, 72 key typewriter style keyboard with 18 programmable keys.
SPEED  4 Mhz
CO-PROCESSOR  Motorola 6845 (video controler)
RAM  64 KB
TEXT MODES  80 chars x 25 lines
GRAPHIC MODES  virtual 160 x 100 through graphical characters
COLORS  built-in 9'' non-glare green phosphor screen
SOUND  No sound
SIZE / WEIGHT  46 (W) x 41.5 (D) x 21.5 (H) cm / 15kg
I/O PORTS  Two RS-232C serial ports, one Centronics-type parallel port, communication socket (built-in modem) RJ11C modular telephone jack
BUILT IN MEDIA  two 5.25'' DS/DD half-height floppy drives (390 KB)
OS  CP/M 2.2
POWER SUPPLY  Built-in power supply unit
PRICE  About $3500

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