TRS-80.org » Roy Soltoff

The Lobo LX-80 Expansion Interface

Matthew Reed — Tue, 21 Apr 2009 14:29:23 +0000

The LX-80 was an alternative to the Radio Shack Expansion Interface that took a different approach to compatibility than the competition. It was originally announced by Lobo Drives International in Fall of 1979, but problems with the supplied operating system meant that it wasn’t released until closer to 1981. The original price was $799 (without memory), although that price had been reduced to $510 by late 1982. Lobo Drives also briefly advertised the LX-50, but it is unclear how that differed from the LX-80.

The LX-80 unit was extremely solid (constructed of 1/8″ thick steel) and was designed to have the Model I monitor rest on top. Although more expensive than other Expansion Interfaces, the LX-80 came with an impressive set of features:

DoubleDuty

Matthew Reed — Wed, 08 Apr 2009 13:53:38 +0000

DoubleDuty is a utility that uses the full 128K of a TRS-80 Model 4 to allow more than one program to be run at one time. Introduced by Radio Shack in 1984, DoubleDuty was written by Randy Cook, the author of Model I TRSDOS and VTOS.

DoubleDuty works by creating three sections, called partitions, out of the Model 4 memory. Partitions one and two each contain a complete Model 4 TRSDOS system. The third partition is reserved for running TRSDOS library commands.

The Programmer’s Guide To LDOS/TRSDOS Version 6

Matthew Reed — Tue, 01 Apr 2008 22:50:08 +0000

The Programmer's Guide is my favorite TRS-80 programming book, and in my opinion, the most useful. The chapters include: