OS/2 on ThinkPad 850

The ThinkPad 850 was no ordinary ThinkPad. It was IBM’s high-end portable multimedia workstation, built around a 100MHz PowerPC 603e processor, with a list price of $12,399 (February 1996). The ThinkPad 850 was originally slated (see IBM announcement letter 195-176) to run four major operating systems: IBM’s own OS/2 and AIX, SunSoft’s Solaris, and Microsoft’s Windows NT.

The ThinkPad 850 and its smaller sibling 820 were initially announced in mid-1995 as models 6042 and 6040, respectively. In early 1996, they were relaunched under different model numbers, 7249 and 7247, perhaps to better fit into the RS/6000 numbering scheme. By that time, PowerPC editions of OS/2 and Solaris had been discontinued, and the entire Power Series brand was more or less dead. Not long after, Windows NT for PowerPC was gone, too. With only AIX left, IBM gave up on the idea of PowerPC ThinkPads, slightly refreshed the 850 with a faster CPU and better display, and rebranded it as RS/6000 Notebook 860.

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Posted in IBM, OS/2, PowerPC | 18 Comments

The Central Point Backup Floppy Format

A reader recently asked about the “native” format of Central Point Backup (CP Backup) floppies. Diskettes formatted in this manner are somewhat tricky to work with as they do not use a standard DOS format. A session with Sydex’s AnaDisk helped shed some light on this format. An old (1992) backup on 5¼” floppies was used for analysis.

When the DIR command is ran on a CP Backup floppy, a listing of largely zero-length files is shown. If the listing is not sorted (standard DOS behavior), a message spells out that the floppy does not use normal DOS format and needs to be reformatted for DOS use. If the directory listing is sorted (4DOS or similar), the message may prove difficult to decipher.

The above should imply that CP Backup formats floppies in a way that DOS can recognize, but not work with. AnaDisk immediately shows what the “problem” is: The 5¼” diskette is formatted with a standard BPB, FATs, and a root directory, but shows that all clusters are bad. What’s worse, the BPB indicates a standard 15 sectors per track (SPT) format, but in reality the diskette is formatted with 16 SPT. This will cause severe confusion to any tool (including DOS itself) which expects the BPB to reflect the true format. Continue reading

Posted in DOS, Floppies | 28 Comments

Kids these days…

By sheer accident I stumbled on this document. In summary, it’s about a bunch of school kids working on a computer history preservation project and trying to archive a big box of floppies from George Alistair Sanger, a video game composer better known as The Fat Man. And they’re having all kinds of trouble. Inevitably this T-shirt came to mind (and yes, I do have one of those):

Kids Today...

It is is both amusing and amazing to me that someone might have trouble getting data off of a double-density 3½” floppy (Mac-formatted or not), or that anyone would even try getting software like Norton Backup or Central Point Backup running in DOSBox and expecting it to do anything useful. Continue reading

Posted in DOS, Floppies | 22 Comments

The XDF Diskette Format

In 1994, IBM started shipping software with support for XDF, or eXtended Density Format, first in OS/2 Warp and a few months later in PC DOS 7.0. Some of IBM’s software packages were also distributed on XDF diskettes. XDF allowed the user to format a 3½” floppy which normally holds 1,440KB of data to a special format with 1,840KB capacity (well, almost—see below), or almost 28% improvement. This came at a time when CD-ROMs were not yet ubiquitous and software was distributed on rapidly growing piles of floppies. Since floppies were relatively expensive to manufacture and duplicate, shipping software on, say, 16 diskettes instead of 20 was an attractive proposition.

The XDF technology was not developed by IBM. The inventor was Roger D. Ivey (as can be seen in a XDF disk’s boot sector) and was first licensed to IBM by Backup Technologies, Inc. of Tampa, FL. Roger Ivey had previously written the Fastback PC backup software. Later releases of XDF software list Ametron Technologies, Inc. as the licensor. Ametron is a company specializing in selling intellectual property.

The XDF technology used several interesting techniques to achieve both higher storage capacity and speed. The XDF utilities mentioned “Patent(s) Pending” but there is no obvious record of a relevant patent ever being granted by the USPTO. Let’s take a look at some of XDF’s tricks. Continue reading

Posted in Floppies, IBM | 24 Comments

Why Won’t IBM’s MSPS201.SYS Load?

Recently a minor mystery resurfaced. When IBM’s OS/2 1.2 SE is installed on any “normal” system (either physical or virtual) and the PS/2 mouse driver is installed (the typical choice), the mouse won’t work:

Error loading MSPS201.SYS

The MSPS201.SYS driver is intended for Microsoft (‘MS’) PS/2 (‘PS2′) mice for so-called Type 1 (’01’) aka AT-compatible systems. It should work, and it indeed does work in IBM’s as well as Microsoft’s OS/2 1.3. Continue reading

Posted in IBM, OS/2 | 8 Comments

Detecting Floppy Drives and Media

Detecting floppy drive types and installed media is a far trickier topic than it should have been. In the ideal world, software could determine how many floppy drives are attached, what their capabilities are, and what media is installed in them, if any. In the real world, software can only accomplish some of those tasks.

Detecting whether a drive is present is the only easy part. If a (functioning) drive is present, the RECALIBRATE command will succeed. If no drive is present, recalibration will fail because the FDC will never detect the TRK0 (track 0) signal (typically after stepping 80 or so tracks). If drive presence is detected, the real fun starts. Continue reading

Posted in Floppies, IBM, PC hardware | 18 Comments

Detecting an Empty Drive… Or Not

Detecting an empty drive with a NEC uPD765A or compatible FDC is theoretically easy using the ‘drive ready’ signal. In practice, the drive ready mechanism is completely unusable on IBM PCs and compatibles due to the way the FDC is wired.

AT-style controllers and drives support the disk change line signal which more or less replicates the drive ready functionality. To recap, the change line signal is controlled by the drive (the FDC merely selects which drive should be reporting it) and it goes active when the drive door is open. To deactivate the change line signal, there must be a medium inserted in the drive and the drive must receive a step pulse. Continue reading

Posted in OS/2, PC hardware | 16 Comments

OS/2 2.0 LA and “Large” IDE Disks

Attempting to boot OS/2 2.0 LA (Limited Availability) on many systems built in the last 20 years often results in the following crash:

OS/2 2.0 LA Trap 0

The trap screen claims there was an exception (Trap 0 or division overflow) in device driver A:, but that’s not quite true. The crash occurred in the disk driver (DISK01.SYS) which handles both the A: floppy drive and the C: etc. hard disks. Continue reading

Posted in IDE, OS/2 | 4 Comments

Twenty Years Ago Today…

On July 24th 1993, Microsoft finalized the first release of Windows NT, labeled version 3.1 “to avoid confusion”. This was a big day for Microsoft, although the practical impact on the computer industry was not particularly big, at least not immediately.

Windows NT 3.1 Disks

After years of hyping up a vaporware product originally known as N-10 and NT OS/2, Microsoft finally laid its cards on the table. Windows NT 3.1 was a modern 32-bit, portable operating system, with support for multiprocessor systems. It was designed by a core team of mostly ex-DEC engineers, all experienced system developers, led by David Cutler. But with its 12MB minimum RAM requirement (x86 version; 16MB for the RISC version), NT 3.1 was never going to be anywhere close to a mainstream OS—not in 1993 when MS-DOS and Windows 3.1 reigned supreme. Continue reading

Posted in Microsoft, NT | 6 Comments

UNIX Alphabet Soup

When reading historical UNIX documentation or source code, one is likely to come across various terms and acronyms that are now more or less completely forgotten, even among current developers of UNIX or UNIX-like systems. These acronyms might be the names of tools, directories, organizations, products, or documents.

Following is a random assortment of terms, with brief explanations where appropriate. Note that most acronyms still in current use are not listed. Continue reading

Posted in UNIX | 3 Comments