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

Registered: 05/30/12
Posts: 366
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: 15435
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: 15435
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: 15435
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: 144
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: 366
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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#108359 - 01/06/17 04:42 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
Al Kossow Offline
Senior Member

Registered: 01/06/11
Posts: 144
Originally Posted By shattered
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...


the FM and MFM images use normal FDC bitrates, otherwise I couldn't have imaged them.

there is a mix of 1S FM and 2S MFM IMD files for the diagnostics

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#108360 - 01/06/17 04:50 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 366
indeed, with rate hardcoded to 500000 and a few more hacks it manages to IPL. f.e. this is Textpack A image from bitsavers:

Code:
[:upd765] command read data cmd=06 sel=0 chrn=(0, 0, 7, 128) eot=1a gpl=07 dtl=80 rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(0, 0, 1, 128) eot=1a gpl=07 dtl=80 rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(1, 0, 1, 256) eot=0f gpl=0e dtl=ff rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(1, 0, 4, 256) eot=0f gpl=0e dtl=ff rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(1, 0, 5, 256) eot=0f gpl=0e dtl=ff rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(1, 0, 15, 256) eot=0f gpl=0e dtl=ff rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(2, 0, 1, 256) eot=0f gpl=0e dtl=ff rate=500000


Doesn't run very far though


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#108368 - 01/07/17 05:48 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 366
With ROMs from bitsavers (apparently an older rev), CED and PDD disks boot but still complain about floppy. But hey, I got a Service Request number :-)



+


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#108369 - 01/08/17 11:26 AM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 366
Getting there... bit 6 in floppy status port (8150) apparently reflects 'idle' status of MCU and upd765 both. Diagnostics disks are now usable and CCP/M boots. Textpack does not yet.


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#108394 - 01/10/17 09:33 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 366
Textpack 1 probably crashes because 128KB is not enough memory for it, but simply mapping more memory does not make it work and diags don't detect extra memory as well... So instead, here's how 66-line display is supposed to look. Only works with "new" firmware:


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