View Profile: Eudimorphodon - Vintage Computer Forum

Today, 09:07 AM

Eudimorphodon replied to a thread Force a 1.4MB 3.5" to only act as a 720K drive? (CoCo) in Vintage Computer Hardware

Whoever told you that is misinformed. On a “standard” 1.44mb drive the density selection jumper directly controls the write current, if you insert a...

2 replies | 0 view(s)

January 17th, 2021, 04:48 PM

Eudimorphodon replied to a thread IBM 5160 ? about XT-IDE in PCs and Clones

On the flip side, I sort of wish the XUB configuration software would incorporate direct support for SST flash chips one of these days. The 128KB...

10 replies | 352 view(s)

January 15th, 2021, 07:42 PM

Eudimorphodon replied to a thread Composite color artifacts: made by design or happy coincidence? in PCs and Clones

The details give me a headache, but the long and short of it is the circuitry that has to trap out the narrow bandwidth chroma pulses and compare...

19 replies | 330 view(s)

January 15th, 2021, 07:22 PM

Eudimorphodon replied to a thread Composite color artifacts: made by design or happy coincidence? in PCs and Clones

But the chroma data isn’t shoved into the back porch, only the color burst lives there. (Which is the sync/phase reference for the chroma data...

19 replies | 330 view(s)

January 15th, 2021, 04:08 PM

Eudimorphodon replied to a thread Composite color artifacts: made by design or happy coincidence? in PCs and Clones

It's *possible* in CGA's case that IBM never actually thought of it and the fact that the hardware is capable of it is a happy accident resulting...

19 replies | 330 view(s)

January 15th, 2021, 11:22 AM

Eudimorphodon replied to a thread Adding a CF card slot to a 5170 without wasting an expansion card bay? in PCs and Clones

A stock 5170's going to have an MFM + FDC board in it, not IDE, of course. But if you put a generic IDE/FDC card in there and want to just play the...

22 replies | 544 view(s)

January 14th, 2021, 03:09 PM

Eudimorphodon replied to a thread Adding a CF card slot to a 5170 without wasting an expansion card bay? in PCs and Clones

Just tossing this out there: they make IDE-to-SD and even IDE-to-Micro-SD boards that you could cable up instead of a CF adapter if you want...

22 replies | 544 view(s)

January 13th, 2021, 06:30 PM

Eudimorphodon replied to a poll System architecture for a Z380 TRS-80 compatible. in Tandy/Radio Shack

What are you planning to use for the video output hardware? And keyboard input, so far as that goes. (Interface to an actual matrix, or some kind of...

19 replies | 330 view(s)

January 13th, 2021, 05:50 PM

Eudimorphodon replied to a thread 2021 Vintage plans, and 2020 lessons learned. in General Vintage Computer Discussions

So, my list for 2021 shakes out something like this: Build a complete "working" computer based on the video dingus I've been futzing around with...

1 replies | 98 view(s)

January 12th, 2021, 05:46 PM

Eudimorphodon replied to a thread Dr. Suding questions in General Vintage Computer Discussions

... so, in other words they successfully copied the *behavior* of the “canonical” 8080 accurately with the Z80. That says nothing about the hardware.

21 replies | 452 view(s)

January 12th, 2021, 01:58 PM

Eudimorphodon replied to a thread Dr. Suding questions in General Vintage Computer Discussions

Electrically the 8080 and the Z80 aren't very much alike at all. The 8080 has an 8-bit ALU <strike>and a multiplexed address bus</strike>(*), the...

21 replies | 452 view(s)

January 12th, 2021, 10:24 AM

Eudimorphodon replied to a thread Dr. Suding questions in General Vintage Computer Discussions

Grrr. That one rankles me every time I see it. I understand he's a nice enough guy and means well, but he should know better. Re: the "slow scan...

21 replies | 452 view(s)

January 11th, 2021, 03:52 PM

Eudimorphodon replied to a thread Do VGA monitors distinguish between NTCS and PAL? in PCs and Clones

Here's a mind-numbing cross reference of Commodore 1080/1084 family monitors. The vast majority of the individual SKUs supported both analog and CGA...

12 replies | 382 view(s)

January 11th, 2021, 10:57 AM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

My TRS-80 Model I came with one of those fabric glare filters stuck to it. I did inexplicably like it a lot; obviously it doesn't actually help with...

21 replies | 679 view(s)

January 10th, 2021, 07:49 PM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

Don't run video modes that the attached monitor doesn't natively support. I mean, the reason it faked shades of gray like that was because if you...

21 replies | 679 view(s)

January 10th, 2021, 07:46 PM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

The idea of such a thing did actually occur to me, but here's the painfully obvious problems that to my mind prevent it from working on even a...

21 replies | 679 view(s)

January 10th, 2021, 05:05 PM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

I'm pretty sure the placebo affect was depressingly significantly responsible for the relief people claimed to feel after sticking all kinds of...

21 replies | 679 view(s)

January 9th, 2021, 08:03 PM

Eudimorphodon replied to a thread Address decoder revisited in S-100

That was a cut-and-paste for an earlier version that was designed to blow PROM "fuses" made out of barbed wire for programming the ENIAC?

12 replies | 466 view(s)

January 9th, 2021, 04:47 PM

Eudimorphodon replied to a thread Address decoder revisited in S-100

Heh. GALASM so far as I can tell is an intentional clone of PALASM; from some brief digging on the latter the syntax looked almost identical to me;...

12 replies | 466 view(s)

January 8th, 2021, 11:21 PM

Eudimorphodon replied to a thread Address decoder revisited in S-100

I recently did a video about using GALASM, a simple open source logic compiler with pretty elementary syntax, to do combinatorial and registered...

12 replies | 466 view(s)

January 8th, 2021, 10:00 AM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

Pretty sure the grayscales on the Deskpro monitor are real instead of interframe PWM so you're probably good unless the basic refresh rate is an...

21 replies | 679 view(s)

January 7th, 2021, 02:21 PM

Eudimorphodon replied to a thread Writing Mac 800kB disks in Later Apple (68000+ based machines - Mac, Lisa, etc.)

According to this datasheet for an early Sony mechanism it did have a 600 RPM motor (they intended it to be used with 500kbs controllers, not the...

29 replies | 994 view(s)

January 7th, 2021, 01:29 PM

Eudimorphodon replied to a thread Writing Mac 800kB disks in Later Apple (68000+ based machines - Mac, Lisa, etc.)

Apple had a massive, raging case of NIH Syndrome in the early 80's. Remember, the 3.5" Microfloppy drive only ended up in the Mac at all because of...

29 replies | 994 view(s)

January 7th, 2021, 12:59 PM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

... and it'll give you an *amazing* headache if you run it on a lower-persistence amber monitor instead of the 5151. Speaking from experience. It's a...

21 replies | 679 view(s)

January 7th, 2021, 11:26 AM

Eudimorphodon replied to a thread Has a game ever used the IBM 5151's "long" P39 phosphor to get around charset limits? in PCs and Clones

So far as I know the 5151 was only in green. It's possible that units with replacement CRTs in a different color exist, there were companies like...

21 replies | 679 view(s)

January 6th, 2021, 11:19 AM

Eudimorphodon replied to a thread Writing Mac 800kB disks in Later Apple (68000+ based machines - Mac, Lisa, etc.)

My gut suspicion is the flux reader issues people complain about are more likely to be the software that has to interpret the transitions getting...

29 replies | 994 view(s)

January 6th, 2021, 10:05 AM

Eudimorphodon replied to a thread Free donation of a Morrow MD3 in California in CP/M and MP/M

I'd be interested but I have too many things on my plate right now, including a basket-case Northstar filling my CP/M dance card. But thank you for...

4 replies | 289 view(s)

January 6th, 2021, 08:58 AM

Eudimorphodon replied to a thread Writing Mac 800kB disks in Later Apple (68000+ based machines - Mac, Lisa, etc.)

Yes, but the issue is the controller, not the drive... at least with a couple asterisks: Asterisk the First: Not that it makes a material...

29 replies | 994 view(s)

January 5th, 2021, 01:32 PM

Eudimorphodon replied to a thread 8-bit EGA ISA card for IBM 5160 / 5130 CGA monitor in Vintage Computer Items Wanted

I think the card I had was a WD Paradise, but it's been too long to say with any reliability. Also can't say for sure what software caused the...

5 replies | 275 view(s)

January 5th, 2021, 11:06 AM

Eudimorphodon replied to a thread 8-bit EGA ISA card for IBM 5160 / 5130 CGA monitor in Vintage Computer Items Wanted

The card you really want is an ATI EGA Wonder. (OR an early "VGA Wonder" that includes the 9-pin digital monitor port, it can fully emulate an EGA...

5 replies | 275 view(s)

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