IBM 5155 Portable Personal Computer: An Introduction

This is the IBM 5155, their first luggable PC. It was their answer to the Compaq Portable and wasn't that successful probably due to it being much more expensive. Despite that, it was a nicely built machine as typical for IBM and is a wonderful addition to my collection.
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[@vwestlife]

I have not heard of any incompatibility between the early XT motherboard and the V20 chip, although the later BIOS version (from 1985) does add official 3.5" 720K floppy drive support and faster RAM counting during POST. There's also an easy mod to let you put the full 640K of RAM on the motherboard. The trimpot is for adjusting the color tint of the CGA card's composite video output.

[@RetroPCUser]

I think a 5160 and 5162 (XT-286) can be installed in place as well, but I digress. Currently bidding on one on eBay and I have a Compaq Portable 1 system that I repaired and everything works (to a point, just need to retr0brite the keys and recap the motherboard). I almost got a 5155 back in the summer of 2006 at a thrift store and a big regret. If I got the system back then, it would've been a fun experience to work on.

[@LarixusSnydes]

This was my dad's first computer in 1985. I marveled at the keyboard flip down mechanism. I played several games on it. My favourite was Lode Runner.

[@offensivejerk]

Yussssssss!!!!! The 5155 video at long last!!!

[@kingcrimson234]

Nice overview of this cool piece of computing history! Yes, they are HEAVY beasts! I've got one myself. It's on right now actually connected to an IRC channel. Yours is in slightly better condition than mine, a little nicer cosmetically. I've got a few minor scuffs. I also put a Lo-tech CF-IDE card in it, very handy!

[@pfuchs722]

Kyle was my best student as well. Thank you for recognizing him in your video. Teacher 4 life - Dhr. Fuchs

[@RobertUlrich]

Worked for IBM and was thankful they issued me one with a rolling case. Built like a tank and traded it in for the PS/2 version.

[@danamennerich3282]

still have mine from college! i was the only one on campus with one. helped to have a father who worked at IBM too...

[@kingcrimson234]

No actually if you set the RAM card to 1 MB, it would *not* count to 1 MB on POST. In fact, the machine probably wouldn't even POST. RAM above 640 KB is used as a shared memory area for RAM and ROM on cards, including ROM BASIC and the BIOS. You could theoretically go up to 736 KB, which would end right where the CGA RAM begins at B800:0000, but the BIOS wouldn't recognize it and you'd still be limited to 640 KB in DOS. If a program was designed to use the RAM from 640 to 736 KB, it can be accessed, but DOS itself wouldn't know about it.
You could also technically make a little boot sector program on a floppy that modifies the BIOS data area in 0040:0000 to report 736 KB, and then chainload the DOS boot sector, which would allow it to see and use it.

[@austinramsay]

Sweet. Thanks for the video! Looking around for one if I can get it for a reasonable price just to play around with. May be difficult being a broke college student lol but hoping one pops up somewhere.

[@DusteDdekay]

I put a XTIDE card into mine, so I could keep the two floppy drives installed, and also have a "hard disk" that's easy to transfer files onto. Just wanted to let you know that it works with those :)

[@helthuismartin]

Is it possible to convert the keyboard connector to USB????

[@these_handles_are_stupid]

Was incredibly lucky to snag a 5155 for 180 dollars in Albemarle, NC. How much did you get yours for?

[@robertfletcher3421]

Was'nt the Kaypro first in this portable format. They made great machines and of course, ran CP/M.

[@lmull3]

I want to say it was the Osborne but I think both came out not that far from one another.

[@VSigma725]

@@lmull3 Osborne predated Kaypro by a year, but yeah, really close.

[@mspysu79]

PC DOS 2.1is OK but PC Dos 3.3 would be the best version for that machine.

[@lmull3]

Are there any differences between that and MS-DOS 3.3 that matter that much?

[@mspysu79]

@@lmull3 There are bug fixes and some newly added features, it is a good "Universal DOS" to use on anything from the 8088 through the 386. Some programs, even ones that will run on an XT also require it. If you need a copy let me know.

[@antoninonigrelli661]

I have 7 off them and they all work

[@avabluej5719]

Willing to give one away?

[@hungboss2003]

Can sell me one?

[@helthuismartin]

Its a RJ11 connector,

[@Iot_World1803]

Cool you are good