Think Your Laptop Is Anemic? Try An MSDOS One

If someone gifted you a cheap laptop this holiday season, you might be a little put out by the 2GB of RAM and the 400 MHz CPU. However, you might appreciate it more once you look at [Noel’s Retro Lab’s] 4.8 Kg Amstrad PPC512 He shows it off inside and out in the video below.

Unlike a modern laptop, this oldie but goodie has a full keyboard that swings out of the main body. The space below the keyboard contains the LCD screen, which [Noel] is going to have to replace with an LCD from another unit that was in worse shape but had a good-looking screen. In this video, he gets as far as getting video output to an external monitor, but neither LCD shows any sign of life. But he’s planning more videos soon.

The MS-DOS 3.3 computer’s LCD could emulate a CGA or MDA screen but had no backlight. The 8 MHz NEC V30 processor had 512K of memory, hence the part number. There was also a similar model with 640K of memory and a (gasp) 2400 baud modem.

The power options for this laptop were a bit odd by today’s standards. The computer could use an AC adapter or a car adapter. It could also run on ten C-size batteries. There were also matching external monitors that were able to power the machine.

We’ve seen LCD transplants on this class of machine before, although that one went from monochrome to color. These may not seem very portable, but compared to the earlier “luggable” computers, they were great.

51 thoughts on “Think Your Laptop Is Anemic? Try An MSDOS One

          1. Well yah it can’t run anything that doesn’t fit on a 720 kilobyte floppy at the moment, 0MB of HDD. Now smallest I’ve heard of is 1.2MB linux boot floppies back in the day but it’s ~800KB compressed kernel wouldn’t expand into 512KB RAM very easily, nevermind execute on a non-32bit or MMU less system. IDK if ELKs would boot on 512KB or off 720KB either.

            Windows would load, if you had the 1.x version to do it purely off floppy, or put a small HDD in there and could load 3.0 in standard mode. Doubt you could do anything useful though, think it will launch on about 400k, but whatever is over and above that is all you’ve got for programs, so probably like 64KB after drivers loaded, how big is solitaire or notepad?

          2. Gem 2.0 gets kinda close to feeling like Workbench 1.3 and was officially supported by Amstrad at the time, one of the originally supplied disks would have had it on I think. (At least the 4 pack, red, blue, yellow, green, of disks supplied with the PC1512 and PC1640 desktop cousins did, though I don’t remember which was which color. Those were 360k though so might have fit on 2 720ks)

  1. Interesting. CGA uses NTSC compatible timings, so some one could install a little LCD/TFT/OLED video monitor as a replacement and use Composite (CVBS) or RGBI to interface with it.
    Okay, RGBI would need some bit of tinkering. If the monitor can’t handle SCART compatible RGB signals, a little extra circuits could help to interface with VGA. Some displays are 15KHz tolerant, either because they are also intended for TV sets or because the are also accepting Composite signals.
    That being said, these are just some random thoughts of mine.
    There are other things to consider, whivh I have missed. Like Composite CGA modes or games using NTSC artifacts. They perhaps require a real CRT TV or a sophisticated CRT emulation. ;)

    1. I have one of these (OK, mine is a PPC640)… but I also have other uses for what you’re discussing. I’d really appreciate it if you’d contact me over on Hackaday[dot]io — I have the same name there (starhawk), you can search for it) so maybe we can talk more about this.

    2. I’ve got one of those automotive headrest DVD player screens apart, North American market, so NTSC and internally I see RGB traces marked. I might end up bodging this into an IBM Personal PC restomod if I can’t get the CRT working. IDK what would be better/worse though, bodging in a monochrome TV (Little 5″ portable type) or bodging in the color LCD. Probably I need another shot at the original CRT though, might be the oscillator.

  2. I remember these at the time. They were pretty good value, but the lack of a backlight was an issue even back then, so third party back light upgrades started to appear I believe. I think we described them as portable, rather than laptop though…

        1. Oops, hit return too soon

          As heavy and bulky as it was, the CPU fit under an airline seat, and the keyboard and screen on my lap. Got tons of work done while flying coast-to-coast. Got envious looks every flight. Loved it.

  3. I have a PPC640. These are… interesting. No sound other than the PC beeper, and expansion is… difficult. ISA16-compatible signals *are* brought out to a set of D-subminiature connectors at the back, but they are buffered off the main system. I forget exactly what it is that’s separated other than “something critical enough that the expansion chassis that you could buy to connect to that was essentially useless because of it”.

    I’m pretty sure it was that the external ISA bus was isolated from main memory (i.e., system RAM) but I could be wrong. The point is, if you want a bootable hardcard back there (hard drive piggybacked on its own controller card) or a Sound Blaster, you’re screwed — it’s not going to happen.

    As far as I can tell from the schematics online — I have not yet attempted orderly deconstruction — there is at least a partial internal implementation of some sort of ISA bus internally, for an internal dialup modem. In my own example, this is wired to a pair of sockets issued for use with British Telecom equipment!

    I’m pretty sure, however, that whatever connections run to the modem do not constitute a full standard ISA bus in either the 8bit (ISA8 aka “XT Bus”) or 16bit (ISA16) flavors. Again, I’ve not opened my machine to verify this, in deference to a very close friend with strong feelings for these machines, and the fact that I can be remarkably clumsy at the worst moments.

    A few other notes… the LCD’s lack of backlighting was not its only point of engineering sadness… like almost all such early LCDs, it had very poor contrast. There is a certain art to angling the display and twiddling that knob juuust right, to obtain maximum legibility in anything other than the best of circumstances.

    The floppy drives are 720k — double density. No, 1.44mb disks are *high* density, and that’s different… and most USB floppy drives will fail to read 720k disks no matter what you do. It’s not an age issue, either — they just weren’t programmed to deal with ’em. There are a (very) few exceptions — however, under absolutely no circumstances, as far as I’m aware, will a USB floppy drive *write* a 720k disk. Oh, and there’s no support for larger drives or for HDDs unless you can manage a BIOS overlay.

    As an aside… an interesting historical footnote that may someday be of use to an enterprising fellow smarter than I am… Alan Shugart was a rather enterprising fellow, he got two major products out of one design. See, the way a classic “Winchester” hard drive (ST-412/ST-506 interface aka “MFM Drive”) sends data to its ISA controller card is *remarkably* simple. It has two pairs of lines on that 20pin “data” cable, a +/- pair each for read and write. If the “Write Gate” control line is asserted (‘Write Enable’ is active, in modern terms… it’s active low, so it ‘asserts’ when pulled to 0v Signal Ground potential), and the “+ Write Data” line is pulled higher (more positive) than the “- Write Data” line, a ‘1’ will be written to disk until the “+ Write Data” line drops to a state equal to or lower than the “- Write Data” line. Similarly, if the “Read Gate” control line is asserted (“Read Enable” active) and the “+ Read Data” line is higher than the “- Read Data” line, the computer is to consider that as to be reading out a string of ‘1’s until it de-asserts.

    Sound familiar? It should! In the case of a 1.44mb floppy drive, or a 720k drive (with a bitrate going at half the speed of the 1.44mb drive!), the “+ Write Line” is called “Write Data” and the “+ Read Line” is “Read Data”… i.e., Data In, Data Out, respectively. They’re both referenced to 0v Signal Ground… as are the (active-low, I’m 99% certain) Write-Enable and Read-Enable lines. The difference? To get a 720k floppy drive equivalent interface, you… hook a comparator across the +/- Data Read line of your Winchester drive and make sure the – Data Write line is grounded and the + Data Write line asserts to +5v aka VCC. Everything else is literally just wire-harness work, a straight-up pinout adapter.

    Seems to me there’s some potential here. You could do one of two things… either (a) wire an MFM drive as Drive B:\ this way, replacing the second floppy drive, and boot from a floppy with a bootstrap containing a BIOS overlay that then called the rest of the system from the HDD, although you’d be stuck using a 720k floppy drive for Drive A:\ in that case, or you could (maybe?) create a custom BIOS patch-set for various computers and BIOSes (a minor industry unto itself, sadly) to stick the overlay in the existing ROM. I have a couple other ideas (a “VGA BIOS”-style trick where you have a *second* ROM for the machine to address in addition to the main system BIOS, that has an adjacent memory address, or… I wonder if it’s possible to partition off a 720k-sized portion of that drive and have the drive lie to the rest of the machine about it?) but IDK.

    I have one other idea… this one’s a bit more wild-eyed. You know how you can swap controller cards on IDE HDDs where the card cooked but the mechanical bits are fine, and if you get it exactly right you’ll get a working HDD… but if anything is at all wrong, you lose your data? I wonder if one could take a modern, smaller HDD, and create a custom controller for it that made it act like a giant floppy disk… ditto for eg an SD Card.

    Anyone wanting to discuss this stuff, please contact me on Hackaday[dot]I. My username there is the same (starhawk) as here. Nothing against Hackaday or the staff or anyone, I’m pretty sure it’s a limitation of the underlying (tweaked-out WordPress, if I had to guess) platform, but the way Hackaday serves up reply notifications to these comments simply doesn’t work for me. (Specifically addressing the staff: all y’all are cool, and I’m absolutely not complaining! It’s me, not [Hackaday]. You guys are *fine* :) )

        1. I knew both but wasn’t quite clear on first read whether he was saying Sugar hacked up Shugarts implementation to cheap it out for this machine or was about original design of the ST-412.

          Though I think a point to note about XT class Amstrads and floppies in general is that they implement Drive A/B 1/0 “properly” and not with the twisted cable.

    1. > (…) however, under absolutely no circumstances, as far as I’m aware, will a USB floppy drive *write* a 720k disk.

      Well, that’s not true. I used a USB floppy drive to *write* 720kB disk specifically for the PPC512. My father got one from someone at work recently without any system disks and we managed to get it running. Luckily I had stashed a pack of 3.5″ floppies and a USB floppy drive my wife got >10 years ago with her laptop.

      I wasn’t able to format 1.44MB disk as 720kB though, until I put some tape over the “high-density hole”. After that everything went smoothly. Oh, and I did all that under Linux, so maybe it’s a question of a different operating system and its USB floppy driver?

      1. Windows 7 up have some floppy drive irregularities. i.e. doesn’t work like it should, USB or internal. I’ve had to use XP machines to make boot floppies. 64bit versions are particularly screwed.

  4. Nice. Laptops back in those days had HANDLES. Yes, this is directed at you all of you dumb laptop manufactures of today.
    My old 1985 Toshiba T1000 with its MSDOS3.3 embedded in ROM, 640k of RAM and its 8088 processor — HAS A FRIGGIN HANDLE !.

    Bring back the handle to laptops.

    1. i miss my T1200 … the one with a HardDrive

      sadly the HDD in mine bit the dust WHEN DUST GOT INTO IT AFTER I OPENED IT.
      i now know not to do that, or damage any “stickers” on the cover ;P

  5. Can you actually buy a laptop new in-store today with a CPU at 400MHz base as the article suggests? Even the cheapest chromebooks with Intel Atoms run at 1.1GHz base, with boosts up to twice that. Cheap netbooks seem to run at similar speeds.

    1. As an aside the last 400Mhz laptops I recall were bizarre MIPS based netbook jobbies circa 2011.

      They ran on one of the CPUs that’s commonly blobbed into the cheapest game emulator handhelds a JZ. There was also a similar and faster offering using a VIA WonderMedia 8750 part.

      1. I have one of those abominations. I got mine non working, and it’s still not. There was half a dozen of them all pretty much identical internally, but this one, although similar, is enough different that none of the tricks divined for those seem to work. Last thing I did to it was start trying to get the pinout for the LCD, planning to hook a BBB to it. Maybe I’m a hopeless romantic, but if I saw a working one, I’d pay as much as a whole $5 just to see what it can do if you strip it right back to bare linux and put your own crap on it.

    2. 400MHz is a weird pairing with 2GB of RAM. As a reference one of my older laptops was a 700MHz PIII-M, but maxed out at 256MB of RAM (half of that soldered in). The few GB of RAM standard was a ~2010-era (2007-2013) thing at which point CPU clocks were hovering around 1GHz even for cheap things (downclocking to ~400MHz most of the time but that’s not what’s printed on the box).

      1. In theory I think you could take a PIII system up to 2GB, but there’s practical difficulties against it. Manufacturers were often only putting 3 DIMM slots in, because the 4th could pick up too much interference, or the drives weren’t quite strong enough and it made the system unstable. So maybe you’d get your 4 slot board working with good single sided 64MB DIMMs, but things would get hairy with double sided 128MB. So the prospect of trying to get huge double stacked 32 chip 512MB DIMMs working on a four slot seems remote, if you can find them. i810 boards supported 256Mbit DRAM but 440s didn’t. I don’t think I ever saw an i810 with more than 2 slots either, but I ain’t seen it all, quite. Possibly you could get an apollo based board that liked 256Mbit AND had 4 slots, but everyone claimed VIA had sucky/flaky i/o from about 98 thru 2002, so IDK if you get a stable system anyway.

    3. DIY it. There are thin clients using VIA CPUs and chipsets that run at 400MHz, some of the older HP ones did it IIRC. There’s a UK site called “ParkyTowers” (Google it!) that will help you a lot. If you need a battery system, I can help if you can Arduino even a little (*I* can do this and I’m dangerous around those!), poke me on the Projects side in the Messages/Chat thing, seriously.

      Be warned, though, that VIA CPUs are HORRIBLE. They are descendants of the IDT WinChip, which was specifically marketed to an area of computing that has long since vanished — the specific subset of office, “embedded”, and other ‘low-power’ applications which do NOT need floating-point mathematic operations as a matter of routine. The WinChip *could* do them, but a Fifties Guy with a mechanical adding machine in dire need of an oil can would be considerably faster!

      The VIA CPU subarchitecture is derived from the WinChip intellectual property legacy and it continues to be hobbled, to this day, by that same issue.

      You can tell if you’ve ever tried to use one. I have an HP T5630w thin client with a VIA 1GHz CPU and an HP Mini 5102 netbook with an Atom N450. Both have 2gb RAM. Both are almost literally physically painful to use because of how slow they are, but the HP Mini comes out looking like a “feed the beast” gamer rig that has the power requirements of Clark Griswold’s Christmas lights (and drives *eight* considerably better displays) compared to the T5630w, because of that freaking VIA processor and the fact that it can’t add three and four without removing its socks!

      They’re dirt cheap on eBay, though! Oh, and if you wind up with a Wyse C-series model… find a Debisn- or Ubuntu-based distro with a version of the XWin “openchrome” driver newer than 0.3.3 and graphics will work (this may be a bit challenging, those boxes are 32bit). Look up openchrome bug #91966 for that story… and, you’re welcome ;)

  6. Just a note, if you boot off original DOS disks by touch and feel (No video) you’re probably getting prompted for time and date when floppy stops crunching, so hit return twice, then try dir, or launching laplink or whatever blind.

  7. My Mom has one of these in a closet somewhere. She bought it from Home Shopping Network. It was so anemic, but very portable for the time and it wasn’t that expensive for it’s time. She hasn’t pulled it out in ages so I have no idea what shape it’s in now.

  8. Looks vaguely familiar. I think DAK sold something similar way back then. As to a proper portable, the Model 70P IBM that used to be part of our on-call rotation was always fun. Its 1 color plasma display, 2400 baud dialup modem and all steel case weren’t much fun even then. (the job was even less)

  9. Did anybody ever figure out the power supply issues with the PPC512? There was a specific order you had to connect the power cord to the wall and the PC or the power supply would self-terminate in a puff of smoke. Maybe it was just the 240v models but I witnessed three die that way. I remember using mine to play Sim City and Rocket Ranger, and programming in Turbo Pascal.

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