Posts in the “General” Category - page 2

LDOS and LS‑DOS: 2012 and Beyond – The Patch Files

I used TRSTools to apply my 2012 date extension patches because I wanted to make the update process as easy as possible for people using an emulated TRS‑80 with virtual disks. But for those of us with a “real” physical TRS‑80, or who just want to update their disks the old-fashioned way, here are the free patch files for my 2012 date extension update.

There are three different sets of patches for three different operating systems: Model 4 LS‑DOS 6.3.1, Model III LDOS 5.3.

LDOS and LS‑DOS: 2012 and Beyond – A Solution

To extend LDOS and LS‑DOS file dating past 2011, I decided to use an approach that I devised back in 1993 when I was first writing PERUSE, my TRS‑80 file utility. My method stores the new date in the same fields in the directory without taking up any more space or taking away any more file passwords. This approach is automatically compatible with all LDOS/LS‑DOS disks and I have yet to encounter a file for which this dating scheme fails.

LDOS and LS‑DOS: 2012 and Beyond – Technical information

The reason dates past 2011 aren’t allowed in LDOS and LS‑DOS relates to the way the year is stored in the TRS‑80 disk directory. All major TRS‑80 operating systems used roughly the same format for the directory. That format was derived from both the original Model I TRSDOS and VTOS 4.0 (both written by Randy Cook).

In the original date format (VTOS 4.0 and later), the date was stored in bytes 1 and 2 of a directory entry. Specifically, the file year was stored in three bits of byte 2.

LDOS and LS‑DOS: 2012 and Beyond

Nothing makes an operating system feel more antiquated than having an expiration date. For TRS‑80 users, that expiration date is just around the corner. Model 4 LS‑DOS and Model I and III LDOS will stop accepting the date in 2012 and the only solution is to disable the system date or lie about the year.

I happen to believe that LDOS and LS‑DOS still have life left in them, so I have developed a set of patches to extend date handling to 2079.

A Tribute to Rick Hanson

I was saddened to learn that Rick Hanson, long time TRS‑80 Model 100 evangelist and enthusiast, died on April 30, 2011. He was the founder of Club 100, a very important Model 100 user group that began in 1983 and still exists today at

Through Club 100, Rick Hanson repaired Model 100’s and provided them to people and groups that needed them, including newspapers and relief organizations.

Correcting the LS‑DOS 2012 Problem

Several people have contacted me over the past few weeks to ask if I can do anything about the LS‑DOS 2012 problem. The short answer is yes, but here is a brief summary of the "2012 problem" for those of you who don’t know what it is.

All of the major TRS‑80 operating systems (including TRSDOS 6 and LS‑DOS 6) modeled the way they stored disk files dates on the file dating scheme created by Randy Cook for his VTOS 4.0 operating system. VTOS 4.

The World Power Systems Fraud

In March 1979, a company named World Power Systems began running multi-page advertisement in many popular computer magazines, including Byte, Creative Computing, Interface Age, and Kilobaud Microcomputing. World Power Systems, founded by Jim Anderson, advertised a number of interesting and unusual products for the TRS‑80 and S-100 computers at prices that seemed almost too good to be true.

Model I Level II BASIC ROM Versions

The original TRS‑80 Microcomputer System, later known as the TRS‑80 Model I, shipped with Level I BASIC when it was introduced on August 3, 1977. An improved Level II BASIC written by Microsoft was announced at the time but was released some time later.
Radio Shack used four different versions of the Level II ROM over the lifetime of the Model I, even though the part number (26-1120) remained the same.

The Atari Anti-Piracy Advertisement

In late 1981, Atari began running an unusual full-page advertisement titled “Piracy: This game is over.”

Version Numbers

Computer software has always used version numbers, but there have been many different ways of managing them. (For an interesting history of version numbers, see the article The Amazing World of Version Numbers by Harry McCracken.)

Most personal computer software followed a consistent pattern of major and minor version numbers.