Author Topic: EEVblog #955 - World's First Portable Computer Teardown  (Read 10338 times)

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Offline EEVblog

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EEVblog #955 - World's First Portable Computer Teardown
« on: December 12, 2016, 11:19:19 pm »
What's inside the world's first portable microcomputer?
The Osborne 1 from Osborne Computer Corporation torn down.
An Adam Osborne and Lee Felsenstein design.
ROM Dumps:
http://www.eevblog.com/files/Osborne1-ROM-RevE-1-44.BIN
http://www.eevblog.com/files/Osborne1-CharROM-RevA-7A3007-00.BIN

 
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Offline TheRevva

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #1 on: December 13, 2016, 12:50:26 am »
I'll take a dig around in my old junk piles as I'm pretty sure I have a set of CP/M 80 boot floppies in there somewhere
(For that matter, if the ROM BIOS was written to the specs, then we can generate new boot floppies - Gary Kildall would possibly be unimpressed though)
 

Offline amspire

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #2 on: December 13, 2016, 01:44:27 am »
My first portable computer was a Bondwell that was basically a big improvement to the Osborne at a much cheaper price.



Really had fun on this. There were a few instant compilers available for cp/m  - I had Borland Pascal and a C compiler from another company that were really amazing. These are very slow computers, but these compilers would compile and run instantly. At university, I had to do computer programming on computer card decks, and pick up the results the next morning. To be able to compile and run genuine C instantly on a home computer was mind-blowing.

The Bondwell came out in 1984 - so why would anyone be using a CP/M computer in 1984?

I was using PC compatibles at work (NEC computers as their monitors killed anything IBM produced), but the original PC price in Australia was incredible. When the IBM pcs were available with the 10MByte hard drive (yes Mb , not GBytes), you could easily spend $10,000 at Computerland. This was about the same price as a new Mazda 323 car at the time.

The Bondwell CP/M portable was, from memory, sub $1000 and there was a lot of readily available and cheap software. My CP/M C compiler was $49 which was a bargain as any professional C Compiler usually started at hundreds of dollars into the thousands.

The first PC I brought was shared with my brother in about 1986/7. It was a $2000 pc clone (a 80286 I think) but at the time the RAM prices were through the roof. To get the 4MByte expansion memory card (which you did need) cost us $4000 extra.

Before the Bondwell, we did have a Australian designed Microbee (about $400 I think), but it used an audio input/output to a cassette tape for storage and needed a monitor or tv (not cheap then). A nice build but the moment I got the Bondwell, I never touched the Microbee again.



 

Offline Silveruser

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #3 on: December 13, 2016, 02:41:11 am »
 >:DBrings back memories. I bought one of the first batch shipped to Canada! Yes I did also get the external 12in monitor to go with it. I also had it upgraded a year or so later for double sided drives and 80x24 display. That second board may have been the display upgrade. I remember a huge rats nest of wires after the upgrades. I believe I might still have disks and manuals somewhere, sadly the computer made the trip to the dumpster at my last move. It had long since failed working and was replaced by new Panisonic luggable with MSDos and a plasma display.  If I recall the service manual had a lot of info on some of the design problems they faced in the day. Worth noting it had 128k of ram, twice what the Z80 supported, they used bank switching. I believe to load most of OS in one bank and programs in the other. BTW the keyboard can be used to prop up the main case making the screen at little easier to read - might be the reason it is so thick.

George
« Last Edit: December 13, 2016, 02:47:24 am by Silveruser »
 

Offline GumUlf

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #4 on: December 13, 2016, 02:48:25 am »
At around 12 min into the video Dave uses two multimeters as feet for the Osborn 1. First I thought it was the EEVBlog BM235, but at around 12:30 you can see one of them in the lower right corner. It is not a BM235, but it almost looks as if it has the EEVBlog logo at the top. Is this a new EEVBlog multimeter, or is it an other model with a blue case and something that looks like it might read "...log" at the top of it? What multimeter could it be?
 

Online Brumby

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #5 on: December 13, 2016, 03:19:44 am »
At around 12 min into the video Dave uses two multimeters as feet for the Osborn 1. First I thought it was the EEVBlog BM235, but at around 12:30 you can see one of them in the lower right corner. It is not a BM235, but it almost looks as if it has the EEVBlog logo at the top. Is this a new EEVBlog multimeter, or is it an other model with a blue case and something that looks like it might read "...log" at the top of it? What multimeter could it be?

Become a 'Supporter' and you will know.

.... but there has been an indication that we might see something more public:
Quote from: EEVblog
Early in the new year ...
 

Offline amspire

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #6 on: December 13, 2016, 03:25:12 am »
Where did you get a Bondwell 12 in Australia? Dick Smith was only selling the model 14 and it was $2495 IIRC. Yeah not many people were buying CP/M machines in 1984.

I wish I'd kept my BW14.
Ours must have been a Bondwell 14 - definitely had the 128k of ram and the 360K drives.

I cannot remember were it came from - not Dick Smith. I have a suspicion it was purchased in the US.

Along the way, it disappeared  - probably in a move. If it ever turns up again, I probably still have many of the disks for it.
 

Offline codfish28

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #7 on: December 13, 2016, 05:18:23 am »
The later revisions of the Osborne 1 were available with a 80 column display and double Density 182k floppy drives. I have one of the later Ozzy ones with both of those features And just like most osbornes it still works 100%.
https://en.wikipedia.org/wiki/Osborne_1
http://oldcomputers.net/osborne-1.html
 

Offline bktemp

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #8 on: December 13, 2016, 06:47:00 am »
After seeing the (already cracked) RIFA caps in the power supply, I totally expected to hear a large bang when Dave powered it up.

Dave, before turing it on again, replace the X2 caps in the power supply!
Or have the highspeed camera running...
 

Offline kalleboo

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #9 on: December 13, 2016, 09:12:52 am »
So from codfish28's second link, it looks like that daughterboard with the links everywhere onto the motherboard was a later (1983) display upgrade for 80 lines (which is also why the RCA jack doesn't have a label on the front - it was added in after the fact)
 

Online Fungus

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #10 on: December 13, 2016, 11:48:25 am »
It's often been said that you can never have too many multimeters, but... when you start using them as door stops, I dunno.



« Last Edit: December 13, 2016, 11:50:01 am by Fungus »
 

Online Fungus

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #11 on: December 13, 2016, 12:10:49 pm »
Looks like they designed the main board without video (RS232 terminal?) then figured out a way to get video without modifying that.

The CPU-on-other-board thing is bizarre. Or genius, I'm not sure which.

« Last Edit: December 13, 2016, 01:51:56 pm by Fungus »
 

Online Fungus

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #12 on: December 13, 2016, 01:53:07 pm »
A little research, ie. Wikipedia, shows that Osborne offered a "Screen Pac" 80 column upgrade. Interestingly developed by a couple of Aussies.

Maybe the horrible hack was just Osbourne planning ahead.

 
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Offline lol36

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #13 on: December 13, 2016, 02:48:35 pm »
There is a guide to get yourself a "new" boot floppy disk: http://www.classic-computers.org.nz/blog/2011-12-23-disk-from-images-cpm.htm.

I guess you can use DOSbox (or any other alternative) to get around the 'windowsless environment' problem.

BTW, a floppy drive on eBay is a few dollars at most (I haven't searched too hard for a cheaper price)
 

Offline rollatorwieltje

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #14 on: December 13, 2016, 09:23:14 pm »


Is that really the reset button under the delete button? That's just evil :palm:

The keyboard layouts of these early machines are always interesting. We had a Philips P2000C in the museum at university, it also had some funky keys. Most notably the "jump" key that worked like home/end/pgup/pgdown depending on the arrow key you pressed after it, and the numeric pad having separate buttons for inserting 00 and 000. It also had both shift lock and caps lock, for those who were used to the behavior of a typewriter I guess.
 

Offline Kleinstein

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #15 on: December 13, 2016, 10:10:06 pm »
Back in that days there where printers with GPIB / IEEE488 interface available. I remember we had one in school. Comodore PET also used IEEE488 for periphery.

 

Offline shabaz

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #16 on: December 14, 2016, 01:42:30 am »
Fantastic video, I never thought I'd ever get to see the insides of the Osbourne computer in such detail.
I think the comments by @Wilfred makes sense, maybe that board is an add-on afterwards, to provide some higher res external video output. The RCA connector did look like an add-on, because it wasn't labelled on the front panel.
When the board is plugged on, the Z80 and a couple of other parts are unplugged and then plugged onto the add-on board.
 

Offline VK3DRB

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #17 on: December 14, 2016, 02:37:16 am »
It is not the worlds first portable computer. Not by a long shot.

Released in 1975...
https://en.wikipedia.org/wiki/IBM_5100

(I actually had one of these in my home in 1980.)
 

Online Brumby

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #18 on: December 14, 2016, 02:46:51 am »
Talk about flashback....

CP/M, DBase II, Wordstar, dual floppies ... and writing application software.  Getting performance on a 3 file merge on a machine with only 2 floppy drives back then...  Fun and games.

Nice teardown.  There really was a lot of wasted space in there, but I suppose the industry was only getting into portability as the selling point.  Compactness came later.
 

Offline imidis

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #19 on: December 14, 2016, 10:07:11 pm »
It's often been said that you can never have too many multimeters, but... when you start using them as door stops, I dunno.


LOL Great catch!
Gone for good
 

Offline niekvs

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #20 on: December 14, 2016, 10:36:14 pm »
At around 12 min into the video Dave uses two multimeters as feet for the Osborn 1. First I thought it was the EEVBlog BM235, but at around 12:30 you can see one of them in the lower right corner. It is not a BM235, but it almost looks as if it has the EEVBlog logo at the top. Is this a new EEVBlog multimeter, or is it an other model with a blue case and something that looks like it might read "...log" at the top of it? What multimeter could it be?

Become a 'Supporter' and you will know.

.... but there has been an indication that we might see something more public:
Quote from: EEVblog
Early in the new year ...

Hmm... Let's hope, for Dave, he won't get caught by the Osborne Effect and fail to sell any of the BM235's now ;)
 
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Offline djos

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #21 on: December 14, 2016, 11:40:02 pm »
Hmm... Let's hope, for Dave, he won't get caught by the Osborne Effect and fail to sell any of the BM235's now ;)

Lol, it has a much more advanced featureset than the BM235 and I doubt it will competing in the sub $200 category.
The impossible often has a kind of integrity which the merely improbable lacks.

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Offline jonovid

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #22 on: December 15, 2016, 05:08:50 am »
anyone still got a commodore 64 for Dave ?. also I use Test Equipment as stands too.   ;D whatever is just laying around the bench.   
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Offline djos

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EEVblog #955 - World's First Portable Computer Teardown
« Reply #23 on: December 15, 2016, 05:09:39 am »
anyone still got a commodore 64 for Dave ?. 

I like mine too much to send in.  8)

« Last Edit: December 15, 2016, 05:11:42 am by djos »
The impossible often has a kind of integrity which the merely improbable lacks.

Visit my Tindie store for Tandy 1000 Adapters for EX, HX, SX, SL, TX & TL etc
 

Offline jonovid

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Re: EEVblog #955 - World's First Portable Computer Teardown
« Reply #24 on: December 15, 2016, 05:33:30 am »
sadly I sold my much loved C 64  :-[  as upgraded to a new IBM, so we could get into the new fad, at the time, called the World Wide Web.  ;D
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