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#108323 - 01/03/17 01:37 PM IBM Displaywriter (1980) WIP
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 378
Quoting Wikipedia:

Quote:

The IBM Displaywriter System 6580 was a dedicated microcomputer-based word processing machine that IBM's Office Products Division introduced in June 1980.[1][2] The system consisted of a central processing unit, based on the Intel 8086, in a desktop case, a monochrome CRT monitor atop the CPU, a detached keyboard, a detached dual disk drive that used 8-inch floppy disks, and a detached daisy wheel printer. The system booted from an 8-inch floppy disk that stored IBM's internally developed word processing software.

UCSD p-System operating system and CP/M-86 were available for the Displaywriter System but were not its regular Operating System.


Bitsavers has photos, documentation, firmware and some software. "Product Support Manual" and "Maintenance Analysis Procedures" are useful; no schematics, though. The "Displaywriter System Manual" that's mentioned in some IBM's patents probably has everything one would want for development and emulation -- maybe it does turn up somewhere.

p-System manuals are not online either -- "IBM Displaywriter UCSD p-System Assembler Reference Manual S544-2156" could have low-level programming info.

CP/M-86 manual is online -- http://www.nostalgia8.nl/cpm/ibm/cpm6dwrm.pdf but has very little hardware info.

http://www.kbdbabel.org/schematic/kbdbabel_doc_ibm_displaywriter.pdf -- schematic of "Type A" keyboard PCB. There's a "USB mod" for these keyboards -- http://downloads.cornall.co/ibm-capsense-usb-web/ibm-capsense-usb.html

On to MAME WIP... (previously: http://forums.bannister.org/ubbthreads.php?ubb=showflat&Number=108291#Post108291 and http://www.vcfed.org/forum/showthread.php?55404-IBM-Displaywriter/page2)

Nigel Williams of retrocomputingTasmania maintains a Google document with reverse-engineered info (http://www.retrocomputingtasmania.com/home/projects/ibm-displaywriter); we're working together and the progress so far is...



For this GIF I've disabled checks of self-test return codes ("bpset fca8b,1,{do ax=0;go}"), in practice DMA and floppy tests fail, as do parts of system board test (these failures are masked by HLT being a no-op in MAME).

Self-test on this machine is very, very paranoid -- I think I've found a emulation bug in i8255.cpp smile

Code:
@@ -473,6 +473,11 @@ uint8_t i8255_device::read_pc()
        {
                // read data from port
                data |= m_in_pc_cb(0) & mask;
+               if (port_c_upper_mode() == MODE_OUTPUT)
+               {
+                       // read data from output latch
+                       data |= m_output[PORT_C] & mask;
+               }
        }

        return data;

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#108324 - 01/03/17 02:07 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
R. Belmont Offline

Very Senior Member

Registered: 03/17/01
Posts: 15487
Loc: USA
Finding bugs in components is good smile It's one of the reasons we merged MESS in.

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#108325 - 01/03/17 08:20 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
Praxis Offline
Member

Registered: 07/27/10
Posts: 34
Loc: Usually London, sometimes Pemb...
At last! I've finally got something relevant to contribute to the whole preservation / emulation effort.
For years I've held on to a literal barn find of an IBM Displaywriter. It's not in good shape so today I set about opening it up.
Special thanks to Al Kossow and Shattered for their guidance, encouragement, hints and tips.
Here's the photo gallery from today's efforts on the CPU case: http://imgur.com/a/U8i0j

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#108331 - 01/04/17 12:00 AM Re: IBM Displaywriter (1980) WIP [Re: shattered]
Praxis Offline
Member

Registered: 07/27/10
Posts: 34
Loc: Usually London, sometimes Pemb...
Next is the IBM Displaywriter keyboard (UK layout).
Here's the photo gallery from today's disassembly of the keyboard: http://imgur.com/a/ZRAaq

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#108339 - 01/04/17 04:28 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
Praxis Offline
Member

Registered: 07/27/10
Posts: 34
Loc: Usually London, sometimes Pemb...
A brief gallery this time. Exterior photos of my IBM Displaywriter monitor: http://imgur.com/a/j4cUs

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#108340 - 01/04/17 06:28 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
R. Belmont Offline

Very Senior Member

Registered: 03/17/01
Posts: 15487
Loc: USA
It probably is powered off 12 volts through the D-sub. That's not an unknown thing, although it was rare in the CRT days.

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#108341 - 01/04/17 06:43 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
Praxis Offline
Member

Registered: 07/27/10
Posts: 34
Loc: Usually London, sometimes Pemb...
Finally, a gallery of the IBM 6360. An 8 inch dual floppy disk drive that came with the IBM Displaywriter.
This is in better condition that the related items in my collection so I didn't destructively tear this one down. I did however open the cover and take a look around: http://imgur.com/a/ZOqaG

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#108342 - 01/04/17 08:06 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
R. Belmont Offline

Very Senior Member

Registered: 03/17/01
Posts: 15487
Loc: USA
That FDD defines "built like a tank". I'd bet if you cleaned it up a bit it'd work.

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#108344 - 01/04/17 08:43 PM Re: IBM Displaywriter (1980) WIP [Re: R. Belmont]
Al Kossow Offline
Senior Member

Registered: 01/06/11
Posts: 147
They have 200v 50Hz AC Synchronous motors in them, so they won't be of much use in the US

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#108358 - 01/06/17 01:33 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 378
upd765 chip is actually available on system bus (ports 8158, 815A) and with a few hacks I forced firmware to talk to it; unsuccessfully so far -- scan ID phase fails. Maybe the FM bitrate is wrong...

Code:
[:upd765] command seek 0
[:upd765] command done (seek) -[:upd765]
[:upd765] irq = 1
[:upd765] irq = 0
[:upd765] command sense interrupt status (fid=0 20 00)
[:upd765] command read data cmd=06 sel=0 chrn=(0, 0, 7, 128) eot=1a gpl=07 dtl=80 rate=250000
[:upd765] command done (data) -[:upd765]  40[:upd765]  05[:upd765]  00[:upd765]  00[:upd765]  00[:upd765]  07[:upd765]  00[:upd765]

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