The Lobo MAX‑80

written by Matthew Reed

Lobo Systems advertisement

Lobo Systems advertisement from the December 1983 issue of 80 Micro

The Lobo MAX‑80 was a TRS‑80 compatible computer sold by Lobo Systems (originally known as Lobo Drives International). Introduced at the 1982 National Computer Conference (where one could be reserved for a $100 deposit), the MAX‑80 offered an impressive array of features including:

  • a Z80B running at 5.07 MHz (making it one of the fastest microcomputers at the time)
  • 64K of memory standard, with sockets for an additional 64K
  • a double-density floppy disk controller with support for both 5¼″ and 8″ drives
  • a hard disk controller interface
  • video support through a standard RCA phono jack
  • a screen size of 64 by 16 or 80 by 24 with a partially redefinable character set
  • a TRS‑80 style keyboard with CONTROL and ESCAPE keys, as well as F1 through F4
  • one parallel port
  • two serial ports
  • real time clock with battery backup

There was a great deal of interest in the MAX‑80 and articles about it were published in all of the TRS‑80 magazines. A MAX‑80 Users’ Group, MAXIMUL, was formed which published a newsletter devoted to the MAX‑80.


Unlike other TRS‑80 compatibles, such as the PMC‑80 or the LNW80, the MAX‑80 wasn’t hardware compatible with the TRS‑80. It shared some hardware characteristics, such as memory-mapped keyboard and video. But there were many differences from the Model I and Model III, including different disk hardware, no cassette support and no BASIC in ROM. As a result, no self-booting TRS‑80 disks would work on the MAX‑80, whether they were operating systems or games.

In many respects, the MAX‑80 had more hardware similarities to the Model I than the Model III. But in terms of software compatibility, the MAX‑80 was based on the Model III. According to some estimates, 95% of all Model III software (excluding games) would work unmodified on the MAX‑80. Games were a separate problem because they usually relied on direct hardware access and the slower TRS‑80 speed. Almost all major TRS‑80 software packages were compatible, and Logical Systems sold a $10 patch disk of fixes for those that exhibited problems (such as VisiCalc and Scripsit).

Operating Systems

Much like the earlier Lobo LX‑80 Expansion Interface, the MAX‑80 required a special version of LDOS to run TRS‑80 programs. Lobo Systems offered two different operating systems for the MAX‑80:

  • CP/M 2.2, and later CP/M 3.0, came supplied with the MAX‑80 and was regarded as an especially good implementation of CP/M.
  • LDOS, from Logical Systems, was able to run most TRS‑80 Model III programs.

There were two other MAX‑80 operating systems available from third parties:

  • MULTIDOS, from Cosmopolitan Electronics Corporation, was largely compatible with MULTIDOS for the TRS‑80 Model III.
  • MaxDOS, introduced by MicroConsultants and Riclin Computer Products in 1985 and later sold by Bryan Headley, was a patched version of Model 4 LS‑DOS that remained completely compatible with standard LS‑DOS software. This was a remarkable achievement when you consider that the MAX‑80 predated the Model 4.

There were also plans for a MAX‑80 version of DOSPLUS, but I haven’t found any evidence that it was ever released.


The MAX‑80 was a complete computer in a 17″ by 10″ keyboard unit (which consumed only 28 watts). A standard configuration originally cost $820.00 for a 64K unit and CP/M. An additional 64K cost $95.00. Later on, the standard configuration changed to a 128K unit for $945.00.

All that was required to make a complete system was a monitor and disk drives. Many types of standard monitors could be used and Lobo Systems sold a 12″ monitor for $175.00. They also sold a variety of disk drive units, including:

  • dual 40 track 5¼″ single-sided floppy drives for $690.00
  • one 80-track double-sided floppy drive for $1,175.00
  • dual single-sided 8″ floppy drives for $1,185.00
  • dual double-sided 8″ floppy drives for $1,485.00
  • one 4.8 MB hard drive (Winchester) for $2,100.00

Lobo also sold a “well-equipped” MAX‑80 system (128K keyboard unit, monitor, and two 5¼″ drives) for $1599.00.


With its 5.07 MHz processor, the MAX‑80 was one of the fastest microcomputers available at the time. Although its lack of graphics and color deterred some, it remained an attractive choice for those who wanted both CP/M and LDOS compatibility. However there is little doubt that the introduction in 1983 of the TRS‑80 Model 4, a 4 MHz computer which offered both CP/M and complete Model III compatibility, must have dampened interest in the MAX‑80.

In 1985, Lobo Systems announced a new computer called the Mini Max. It was a $795 transportable computer designed to compete with the TRS‑80 Model 4P. I don’t know if any were produced, and both Lobo and the Max-80 disappeared soon after.

MAXIMUL and their MAX‑80 newsletter both outlasted Lobo Systems, ending only in 1989. MaxDOS also remained available until at least 1988.

Categories: Computers


Chuck de Young says:

This is the computer I most regret not having today! I owned one of these fine machines in the 1980’s, and came from a TRS‑80 background, but this was the time period that I was working in CP/M and the Lobo became my main machine. I had dual DD DS 8″ drives, as well as multiple 5.25″ floppies, but never a hard drive.

I remember falling asleep to the clicking and whirring of the drives, and the blinking of the LEDs as some big job was running. I wrote some very good code on that machine, and it is not going too far to save I loved it. Like the Velveteen Rabbit, I put it aside as I moved into the world of the PC, and I actually remember that for awhile I had two, and now I have none, but I do not remember how I parted with it.

I would love to have one again, with the eight inch drives, and all, but I have never seen one for sale. The Max-80 was a great computer, LDOS was a fine operating system, and I have been very fond of other computers I have owned in the 25 years since then, but this might have been the one, the single best machine ever.


Phil says:

Wow – this site brings back memories. I was in high school (or the equivalent) in England and since I couldn’t afford the TRS‑80 I had a Video Genie. A far east copy of the hardware that ran all these games and other software.

I can’t believe that I’d forgotten Starfighter… I played that game for hours and it held my imagination as much as any game since.

Thanks for the site :)

Bryan says:

Yes, DOSPlus IV existed for the Max-80.

Tom Briscoe says:

From the original Small-C article in Dr. Dobbs Journal I was able to create a port to the TRS‑80 using Zilog mnemonics and the Microsoft Z80 assembler. I did most of the work on my Max-80 and later moved up to James Hendrix’s Small-C v.2. I also had CP/M 3 when it came out, but I found a free Z-80 source CP/M clone called ZDOS and managed to get that running, to which I added a free Z-80 assembler I found published in a book. Topping it all off with a small screen-oriented text editor I wrote in Small-C gave me a complete system, entirely in source code. Those were the days!