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

Matthew Reed — Mon, 13 Jun 2011 13:25:51 +0000

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 5.3.1, and Model I LDOS 5.3.1. Each set consists of an installer JCL file and six patch files.

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

Matthew Reed — Wed, 01 Jun 2011 14:09:29 +0000

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. (If you do, please let me know so that I can fix the problem.) With my patches, disks don’t even need to be converted but will just transparently store dates after 2011.

My patches also fix a problem occasionally encountered with LDOS 5.3 and LS-DOS 6.3. If an older operating system was used to copy files onto a date converted disk, then the copied files will still have the older user password field. LDOS 5.3 and LS-DOS 6.3 (which replaced the user password with date and time) will interpret that password as a garbled date and time. The patches check specifically for such files and use the older year instead (providing more accurate results than unpatched versions).

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

Matthew Reed — Wed, 18 May 2011 14:07:21 +0000

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. The maximum value that can be stored in three bits is 7, so the original allowed date range was between 1980 and 1987.

In 1987, LS-DOS 6.3 and LDOS 5.3 were released by Logical Systems and MISOSYS to address the year limit. Extra space was needed in the directory to extend the dating, which both operating systems achieved by removing the access (also known as user) password. This new dating format became known as “extended dating” or “date converted.”

LDOS and LS-DOS: 2012 and Beyond

Matthew Reed — Mon, 16 May 2011 12:52:33 +0000

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. The result is a 100 year dating window, beginning January 1, 1980 and ending December 31, 2079.

The patches are free and there are six patches in the set:

A Tribute to Rick Hanson

Matthew Reed — Tue, 03 May 2011 12:53:10 +0000

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 club100.org.

Through Club 100, Rick Hanson repaired Model 100’s and provided them to people and groups that needed them, including newspapers and relief organizations. He also sold Model 100 peripherals and became the sole source of many items as the market contracted. He played a vital role in promoting new Model 100 hardware such as the NADSBox, a memory card storage device designed by Ken Pettit, and the REX, a ROM/RAM add-on designed by Stephen Adolph. He also ran the Club 100 BBS until October 2007.

Rick Hanson enjoyed promoting the Model 100, and was featured many times in newspaper articles. He also made a memorable August 2001 appearance on Leo Laporte’s television show on the TechTV channel where he demonstrated the durability of a Model 100 by dropping it to the ground without damage. He also later appeared on Laporte’s radio show in March 2008.

He was one of the friendliest people around in the computer world and he will be greatly missed.

Correcting the LS-DOS 2012 Problem

Matthew Reed — Thu, 28 Apr 2011 00:21:12 +0000

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 4.0, released in 1980, allowed file dates spanning 1980 to 1987.

Back then eight years seemed like a long time, but 1988 eventually approached and something more needed to be done. In mid 1987 Logical Systems introduced LS-DOS 6.3 for the Model 4 and MISOSYS introduced LDOS 5.3 for the Model III and later Model I. Both LS-DOS 6.3 and LDOS 5.3 included many enhancements over previous versions, but their primary reason to exist was to extend file dating to 1999. (In the early 1990's, MISOSYS extended file dating even further in both operating systems to 2011.)

There were other date extension packages released at around that time. David Goben released an alternative date extension package for Model 4 TRSDOS 6.2 called T62DOSXT. Vernon Hester extended the file dating of his operating system, MULTIDOS, to 2011, and more recently to 2043.

Now 2012 is less than a year away, and unless LS-DOS and LDOS are updated again, they will no longer able to accept and record the correct date after December 31, 2011. We will still be able to use the operating systems, but having to lie to them about today's date just doesn't seem right.

So, to answer the questions I have been receiving, yes, I can do something about it. I am near the end of development of a set of patches to LS-DOS 6.3 that will extend file dating to 2079, which is probably far enough in the future to not have to think about it for a while. Creating the patches has been tricky because I wanted them to meet several criteria:

They had to be able to read older TRSDOS 6 and LS-DOS 6 disks and correctly report file dates. In other words, it wasn't good enough to just pretend that file dates before 2012 no longer exist.
They had to be compatible with existing Model 4 programs.
They had to be transparent to the user and NOT require conversion programs.
They had to fit entirely within existing LS-DOS code without taking even one more byte of space. This is the hardest part but doable with a lot of effort.

As soon as I have finished creating and testing the patches, I will release them here for general distribution. Then I will create a set of equivalent patches for LDOS 5.3 and release them here as well.

Keep checking back here for more information.

The World Power Systems Fraud

Matthew Reed — Tue, 02 Nov 2010 13:15:00 +0000

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. As it turned out, they were too good to be true; Jim Anderson was actually a prison escapee named Norman Henry Hunt and World Power Systems was an elaborate scam that ended up costing customers and suppliers hundreds of thousands of dollars.

Model I Level II BASIC ROM Versions

Matthew Reed — Tue, 26 Oct 2010 13:39:14 +0000

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. Over the lifetime of the Model I, Radio Shack used four different versions of the Level II ROM even though the part number (26-1120) remained the same. Radio Shack never officially named the ROM versions, or even acknowledged the existence of any version other than the last, so the names used were created by users.

The Atari Anti-Piracy Advertisement

Matthew Reed — Tue, 17 Aug 2010 13:16:00 +0000

In late 1981, Atari began running an unusual full-page advertisement titled “Piracy: This game is over.” It appeared in several computer magazines, including InfoWorld, Byte, Creative Computing, and Softside. Atari also sent copies to a number of software publishers. The advertisement read:

ATARI has led the industry in the development of video games such as ASTEROIDS and MISSILE COMMAND. The outstanding popularity of these games has resulted from the considerable investment of time and resources which ATARI has made in their development. We appreciate the worldwide response from the videophiles who have made our games so popular.

Unfortunately, however, some companies and individuals have copied ATARI games in an attempt to reap undeserved profits from games that they did not develop. ATARI must protect its investment so that we can continue to invest in the development of new and better games. Accordingly, ATARI gives warning to both the intentional pirate and to the individuals simply unaware of the copyright laws that ATARI registers the audiovisual works associated with its games with the Library of Congress and considers its games proprietary. ATARI will protect its rights by vigorously enforcing these copyrights and by taking the appropriate action against unauthorized entities who reproduce or adapt substantial copies of ATARI games, regardless of what computer or other apparatus is used in their performance.

Version Numbers

Matthew Reed — Thu, 20 May 2010 13:10:00 +0000

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. I found this description of the Radio Shack approach to version numbering from the TRSDOS and DISK BASIC Reference Manual to be interesting: