The IBM P75 was the most powerful portable computer released in 1990 as it was the first mobile computer to sport the then cutting-edge, Intel 486 CPU. It was also perhaps the most expensive personal computer that you could commercially buy – depending on configuration, the P75 could be priced north of $18,500 or about $37,500 in 2020 dollars!

This computer was not something that you could pick up at the local computer store – the IBM P75 was a Ferrari (or literally a modern Tesla’s worth) of mobile computing and were to be ordered direct from IBM or an authorized dealer. But this begs the question: why did a computer the size of a briefcase cost as much as a luxury car in 1990?

The Landscape

Let me remind you of the year – it’s 1990. We saw the start of the Gulf War with Iraq invading Kuwait – we also witnessed the launch of the Hubble Telescope and the airing of the first Simpsons episode. The dawn of a new decade was upon us, with pop culture and technological innovation shifted into overdrive.

Intel had just unleashed the next generation i486 CPU, setting the stage for more sophisticated software (most importantly games) and GUI-based multitasking to come. The new 486 CPUs were pricey, however, and only those needing computing horsepower for AutoCAD and the like bought them at first. Other than CPU innovations, color displays had also just hit the market, with the release of the NEC Prospeed CSX – a $9,000+ A/C powered portable, with EGA resolution and 16 Colors. Impressive right? Oh, by the way, the screen measured a massive 8 by 5 inches, and the “laptop” weighed a knee-crushing 19 pounds. Portable computing in 1990 was really just getting on its feet.

Though buying a 19-pound laptop with a palette of 16 washed-out colors may seem comical to us today, other brands had begun to find their footing (and thankfully beginning to take the weight off our shoulders). Portable computers were beginning to be measured in inches instead of feet, though most were still hefty, thick, and now only slightly back-breaking.

That is not to say all laptops in 1990 were overweight – some especially light models had already entered the exclusive “5-pound-or-lighter club”. Though some very early 90s laptops had shed the weight, they had also shed their performance too, with these early “notebook-type” laptops being vastly underpowered. This deliberate reduction of performance was a necessary compromise as high-performance components weighed more and demanded more power. Don’t forget, battery technology at the time was primitive – an average 286 based laptop could barely stay powered for a couple of hours and were not able to sufficiently power a 486-based portable machine in 1990.

Another reason why lighter laptops lacked performance was that miniaturized high-performance components simply did not exist; the miniaturization of high-performance components (like large capacity hard drives, or a low-power-consumption version of the 486 CPU) for use in laptops were on the horizon, but would only become available in 1992.

The need for portable desktop-grade performance in the late ’80s and early ’90s gave rise to “portables.” These were a class of mobile computer that did away with batteries, and instead, crammed as much power-hungry, high-performance components as could be put in a relatively “transportable” package. If you haven’t noticed, we love portables here on Retropaq! (Check out Compaq’s last portable computer, the Compaq Portable 486 from 1992, and the funky lunchbox shaped Compaq Portable 386 from 1987) These portable computers were not designed to be used on a plane; instead, these portable desktop-class computers were intended to be plugged into the wall when you moved from point A to point B.

Although relatively heavy compared to laptops, portables were quite svelte and compact compared to the traditional 80’s luggable. Some were laptop shaped (though really not intended for use on your lap, due to their weight), and others were briefcase shaped. These computers had reduced portability but vastly outperformed battery-powered laptops. Portables were really in a class of their own, with most of the high-end portable pedigree being deployed in exotic applications such as portable file servers, building-worksite AutoCad stations, or even as the personal computers of high-level, high-upper-back-strength executives, who needed power and performance at any cost.

Enter: The IBM P75

The IBM P75 was the most powerful portable computer that money could buy in 1990 by a huge margin. Being the first mobile computer to use the Intel 486 CPU really set the IBM P75 apart. Other high-end portables were running 386 DX’s, which were fast – but the 486 was on a whole other level. People didn’t even quite know what to use a 486 for in 1990, aside from greatly speeding up AutoCAD and acting as portable servers. But, let’s put it this way – a 386 would comfortably run Windows 3.1 with excel and word processing, but a 486 could handle running Windows 95 – where you could surf the net with Netscape Navigator and run SimCity 2000 (albeit in a world of orange) in a separate window with no problem.

In fact, the P75 was described as a portable “server” due to its then-immense computing power. It came with a VGA amber/orange gas-plasma display, capable of simulating 16 shades of grey (more like 16 shades of orange), a full travel IBM keyboard (quite clicky), a large SCSI hard disk, and a floppy drive making it a truly portable desktop-class computer.

Here are the detailed specifications of the IBM P75:

As you can see – its specs are pretty impressive and more fitting of an average desktop computer from, say 1993, which is why the P75 cost as much as a luxury car at the time.

Needless to say, not too many of these IBM P75’s were made – concrete production or sales numbers from IBM are hard to find. However, it’s safe to say whilst there were niche applications for the IBM P75, it wasn’t something your average Joe would be buying. If you had one of these in 1990 – please, please leave a comment and tell us what it was like to use this screamer-rocket of a computer back in the day!

Take a Closer Look at the IBM P75:

• The Most Powerful Portable – IBM P75
• Take a Look Around (The Outside)
• But wait, there’s more – Under the Hood (Interior)
• Tips & Tricks (Restoration: CMOS Battery, Getting POST)
• Booting Up & Configuring the IBM P75

The post The Most Powerful Portable – IBM P75 appeared first on Retropaq.

The IBM P75, like other contemporary PS/2 computers of the period, utilizes a reference diskette to make changes to system settings, including the installed memory size, the assignment of the built-in connectors, and installed options with their location and assignments. You will need this floppy disk to boot your IBM P75 (or P70) if it has been unused for a while, and the CMOS battery has run flat. Once you have run the reference diskette software once, you won’t need to do so on subsequent boots unless you wish to make configuration changes to your system.

You can download a copy of my P75 Reference Diskette here– you need to write the image file (.imz) to a floppy disk (I use WinImage on my Windows 98 rig). Note: my version has already been updated with XGAOPT as discussed here and, my image has files to support the expansion cards on my IBM P75, namely a Sound Blaster Pro 2 MCV (CT5330) and IBM XGA-1 card. But don’t worry – if your P75 doesn’t have any cards or has these specific cards, you will be able to configure your computer with no problem.

If you have other Microchannel cards installed aside from the ones listed above in my configuration, you will need to create installation diskettes or copy the relevant ADF (and perhaps other files) onto the reference diskette. Search for your card, and you will find the ADFs usually on this site.

Once you have created a reference diskette, insert it into the floppy drive and power on – with luck, your P75 should slowly read the floppy disk (The P75’s floppy disk drive will make very slow reads at first – don’t be alarmed, this is normal), and then you should see this amazing screen:

FIRST THING – make a backup of your ref disk! There were complaints of “refdisks” going bad back in the day, and now some 30 years later, floppy disk problems are much more common. I have 3 copies of my ref disk at any one time, and I really have had 2 of them crap out on me one after another!

System settings are stored in CMOS, and data integrity is maintained through an internal non-rechargeable 6V battery. Should the internal 6V battery run low, the computer may not POST successfully as the internal CMOS contents are corrupted. The reference diskette also includes basic diagnostic software (mine seems to indicate problems with my system “planar,” though the computer remains perfectly useable).

Note, if you try to boot your P70 or P75 without an operating system and/or hard disk, the P75 will drop the user into IBM Cassette Basic. Certain other configuration errors arising from corrupted saved configurations and the like can sometimes also result in being dropped into Cassette Basic.

Anyhow, once you have booted your reference diskette and see the delightfully large IBM logo, hit enter, then select “Run Automatic Configuration” – this will automatically detect what Microchannel cards you have installed (if any) and decide on their settings for you.

Though, if you are familiar with setting up a 90’s computer, you will be pleased to see that you can get quite granular with all the settings. I won’t go into that level of detail here, however. To access these settings, select “Change configuration” instead of “Run automatic configuration.” Other menu options, such as the memory allocation map (Display memory map), can help diagnose any booting up errors. The other options are pretty standard, such as setting SCSI devices and changing the time. One interesting thing to note – you can actually set the P75 to act as a remote server through the reference diskette. I can only imagine what the circumstances must have been for a person or organization to require a portable server!

Anyway, once the automatic configuration is complete, the reference diskette will ask you to reset. Then you should be able to install MS-DOS or another period-appropriate operating system you wish by inserting the boot floppy for your installation.

When it comes to running software, the IBM P75 is a fully-fledged 486 based machine and can (obviously) run all MSDOS & Windows software of the period.

The one unique item is the gas plasma display – the internal gas plasma display of the IBM P75 is XGA/VGA, EGA, MCGA, CGA compatible and operates at a maximum 640×480 in 16 shades of grey in VGA mode. Meaning, you can play pretty much all DOS games from the 80s through to the early 90s. The IBM P75 can drive its internal monitor and an external monitor simultaneously. When driving the external monitor only, it can operate at 800×600 resolution in 16-bit (high-color) in Windows 95 using third-party drivers. Note, the VGA monitor is NOT VESA compatible, so it won’t run software (games) that require this.

The advanced hardware on the P75 (advanced for 1990) means that it can run OS/2, MS-DOS, Windows 3 / 3.11, and even Windows 95. Here’s a selection of my favorite games running on the internal gas plasma display (all in VGA), but of course, limited to 16 shades of “grey.” Some games like Wacky Wheels look great, while others, especially Windows 95 games, are tolerable but are probably more fun in their original color palettes.

Here’s a selection of screenshots in Windows 95:

And that’s it! I hope you enjoyed taking a look at my IBM P75. For those of you who have one of these amazing machines and want more details, I suggest that you take a look at IBM’s P75 Quick Reference Guide – there’s lots of detailed stuff in there that I haven’t covered in this post.

Take a Closer Look at the IBM P75:

• The Most Powerful Portable – IBM P75
• Take a Look Around (The Outside)
• But wait, there’s more – Under the Hood (Interior)
• Tips & Tricks (Restoration: CMOS Battery, Getting POST)
• Booting Up & Configuring the IBM P75

The post Booting Up & Configuring the IBM P75 appeared first on Retropaq.

IBM computers were made for big-businesses, governments, and professionals, and the IBM P75 was no different. In fact, I would say the IBM P75 is perhaps the most specialized computer out of the entire PS/2 line. Looking at its exterior, the nondescript box shape of the P75 gives little away as to what it actually is – I’m sure if someone put this on a desk in 1990, some may have thought it to be some sort of futuristic briefcase. Perhaps those who had used an IBM would have seen the badge or recognize the color and guess that within would be a business computer.

Opening up the P75 reveals the treasure within – a full-travel IBM clicky keyboard, a 640×480 resolution VGA gas-plasma screen, and a floppy drive.

The screen, keyboard, and floppy disk drive shown above are in their stowed positions, but all three can be released for use, and the keyboard and screen can have their positions adjusted for comfort.

Here we can see the screen in the stowed position, flat and flush against the vertical case. A gentle pull on both sides of the screen with both hands pulling on the indentations on the screen’s edges releases it, allowing it to be pulled forward and the viewing angle to be adjusted.

NOTE: if you have an IBM P70 or a P75, be *very* careful when you stow the screen. Releasing and stowing the screen from the frame of the computer almost feels a bit destructive in of itself as it requires a bit of force to pull the monitor out – but when you stow the monitor, always push the bottom of the monitor in first before you push in the top of the monitor to lock it in place. Not doing this will break the hinges!

The floppy disk is also similarly stowed and un-stowed – a gentle push on the raised square on the right releases the drive, and it gracefully swings open for you to insert a floppy disk. A very elegant and space-saving design that manages to cram a full desktop package into a standard briefcase. This compact packing of components is even more noticeable when looking at the interior of the P75.

Moving above the unit, we can see the thickness of the computer – definitely not something that you would want to commute to work with on a daily basis. However, if we consider that it is a complete 486 computer, packing 4 MCA-bus expansion slots that were released in 1990 – one can accept its dimensions (and I dare say even admire the design!)

The rear of the unit is similarly well-designed, simple yet functional. Starting at the left, we have the power socket, which is supplies the IBM P75 with A/C electricity through an IEC C14 socket, the PSU accepting 100-240v 3.0A 50-60Hz. At the top of the case, we have a recess to stow the solid metal carrying handle. To the right of that, we have the I/O ports, hidden away with a swinging door. The swinging door actually has a door within a door, which slides up and down to allow for cables to access the various ports. To the left of the unit, we have the standard computer power socket and vents for the exhaust fan.

Taking a closer look at the I/O port and expansion card area behind the door, we can see that the P75 has all its desktop counterparts’ ports. From left to right, we have a SCSI port, an IBM 5.25 floppy disk drive port, a parallel port, a serial port, and a PS/2 mouse port. Yes – the same PS/2 port that came in green and purple on all computers in the ’90s and into the 2000s. This recessed area also allows you to coil up and store the power cable when the unit is in transit.

Taking a look down under – we can see the very official-looking IBM sticker with the model number and manufacturing date – my unit was made in 1991 – hopefully meaning that whoever purchased it paid a little less than the $18,500 sticker price when it was new in 1990. IBM also very proudly displays their FCC Class B certification for a reason. It was meeting the standards of this certification that made the IBM P75 the first 486 based portable for “legal sale and use” in the United States. Other manufacturers, particularly in Asia and Europe, likely had 486-class portables on the market, but they could not be sold in the U.S. as they did not have the FCC Class B certification.

Here is a shot for all you keyboard aficionados out there – and I agree, the keyboard is fabulous to type on. It is remarkable how lightweight they have managed to make the keyboard and still kept it full size. I imagine an IBM model M keyboard would be more “clicky,” but still, this keyboard gives great tactile feedback (much better than any modern “flat-key” keyboard, that’s for sure). As you can see above, the keyboard can be fully detached from the computer (with its connectors to the main unit functioning as legs to prop up the keyboard). The 14 inch rolled coil cable connecting the keyboard and the P75 can be seen in the down in the gap between the two.

There is just something special about IBM computers – even the logo invokes images of big business and ambition for global domination. Though with the passing of time, the logo now serves as a reminder of IBM’s yesteryears. A quest for personal computer domination – a dream that did not quite pan out as expected.

And there you have it, a tour round the exterior of the IBM P75 – a computer for those who needed portability and power, at any cost.

Exactly who would buy an $18,500 (that’s $37,500 in 2020 dollars) suitcase computer in 1990? See: The Most Powerful Portable – IBM P75

Check out what sets the IBM P75 apart: Under The Hood – Looking Inside the IBM P75

Take a Closer Look at the IBM P75:

• The Most Powerful Portable – IBM P75
• Take a Look Around (The Outside)
• But wait, there’s more – Under the Hood (Interior)
• Tips & Tricks (Restoration: CMOS Battery, Getting POST)
• Booting Up & Configuring the IBM P75

The post Looking Around the IBM P75 appeared first on Retropaq.

We can see from the above the interior leaves no wasted space. The system board (or “planar” to use IBM jargon) is flush against the unit’s center plane. The XGA-1 card connects to the system board through the MCA bus, which has a riser card and frame allowing 4 Microchannel Bus expansion cards (the T-shape in the center). The CPU is on a detachable complex card on the top left – indicating that the designers intended the CPU card to be upgradable, but no upgrade CPU cards were ever released. Below this, we have the RAM SIMM slots, which have a maximum capacity of 16 MB (4 x 4MB per SIMM). At the base, we have the PSU and the hard disk making the unit bottom-heavy and giving it a low center of gravity, making it harder to knock over when placed on a table.

Here we can see the processor card up close – excuse my thermal paste – I removed the active cooling heat sink to allow for a better photo. As you can see, I have upgraded this unit to run an AMD 5×86 and have overclocked the system to 144 Mhz (72Mhz /2 *4). Note, the ROM is also stored on the processor card. You can see the two 3V coin cell batteries used to preserve the CMOS contents to the left of the CPU complex.

Here is a closeup of the CPU complex in it’s non-socketed, stock configuration, with passive metal heatsink for it’s Intel 486 DX-33 CPU.

And finally, here is the “system planar” or motherboard removed from the IBM P75 – you can see the Microchannel bus at the top (center) with a connection for the XGA-1 card and then a connection for the riser card. The SCSI BIOS chips are also visible (left-center bottom) above the connector for the power supply. To the right of the power supply connector is the SCSI connector for the internal hard disk. On the very left, you can see the RAM SIMM slots and the floppy disk cable connector below that. To the right, we have the SCSI, parallel, serial, external floppy, and PS/2 mouse ports. If you are looking for a component-level view (more insight into each chip, such as the SCSI controller, DMA controller, etc., then check out 9595 – The Ardent Tool of Capitalism’s page on the P75

Don’t miss the full story on how and why the IBM P75 came to be: The Most Powerful Portable – IBM P75

Also, have you checked out the exterior design? Looking Around the IBM P75

Take a Closer Look at the IBM P75:

• The Most Powerful Portable – IBM P75
• Take a Look Around (The Outside)
• But wait, there’s more – Under the Hood (Interior)
• Tips & Tricks (Restoration: CMOS Battery, Getting POST)
• Booting Up & Configuring the IBM P75

The post Under The Hood – Looking Inside the IBM P75 appeared first on Retropaq.

If you are getting these codes (or any other codes) on boot, check this website for a handy list of IBM error codes, along with their meanings. Most common error codes include PS/2 error codes 162, 163, 201, 221, 165, 14901 – all but the 14901 error code should resolve themselves if you replace the CMOS battery and run the IBM reference diskette. The 14901 error code is a bit more tricky – resolving it usually requires disassembling the IBM P70 / P75 and cleaning the contacts on the graphics card as well as the display power and data cables. Sometimes, a recap of the graphics card may be also needed.

If you cannot get POST, I suggest you consider doing these two things first before moving further:

1. Recap the system planar board, the graphics board, and your floppy disk drive – they use various SMD capacitors, most of which will have failed (see link for list and location of capacitors). Failed capacitors can lead to a boot with nothing displayed or a boot and short beeps. You should be able to boot to the screen above once you have recapped the system board and display card.
2. Replace the 6V CMOS battery – this is needed to save and preserve your system configuration when the computer is off, so you don’t have to redo your setup each time.

Once you have managed to get the computer to POST (as in, you get a RAM count), you need to get your hands on or make a reference diskette.

Create a Reference Diskette by downloading it here for the P70 and here for the P75. Booting from this diskette is the only way you can configure an IBM P75 – there is no BIOS that is normally found on more modern computers.

As mentioned, you will likely need to recap the floppy disk drive to boot the reference diskette. If you need to replace the floppy disk drive, you must replace it with an IBM drive as they have a proprietary pinout that is different from standard floppy drives. Alternatively, you can also create an adapter to use a standard floppy disk drive or GOTEK floppy emulator. It is also possible to use an adaptor to get a standard floppy drive to work in the P70 / P75.

If you are having trouble getting the IBM P75 to POST after recapping or replacing the battery, try leaving the CMOS battery unplugged for an hour. Sometimes, a corrupt configuration can be stored in the CMOS, preventing the computer from booting until the contents are reset. After an hour of leaving the CMOS unplugged, try booting the P70 / P75 with no battery plugged in, then run the configuration from the Reference Diskette. Once the configuration is saved, then (carefully!) reattach the battery plug onto its header pins.

Other issues to consider would be to check the RAM on the motherboard. The IBM P75 supports up to 16 megabytes of RAM through 4 SIMM slots on the motherboard, each of which can accept a 2 MB or 4 MB 70 nanosecond SIMM.

Check if they have been installed correctly or if they require cleaning. I always use isopropyl alcohol and a q-tip to clean connectors on RAM SIMMs or pretty much anything with an edge connector. Also, note that IBM PS/2’s require that the correct “presence detect” pins have been used – these are little solder connections between pads on SIMMs that indicate what kind of SIMM it is to an IBM computer. Basically, the SIMM must be manufactured by IBM for the P70 / P75 to accept them – non-IBM SIMMs, specifically, those that do not utilize the “presence detect” feature, cannot be used unless you modify them.

Take a Closer Look at the IBM P75:

• The Most Powerful Portable – IBM P75
• Take a Look Around (The Outside)
• But wait, there’s more – Under the Hood (Interior)
• Tips & Tricks (Restoration: CMOS Battery, Getting POST)
• Booting Up & Configuring the IBM P75

The post Tips & Tricks – IBM P70 / P75 CMOS Battery & POST appeared first on Retropaq.