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From: Jon Kirwan on 24 Jun 2010 07:21 On Thu, 24 Jun 2010 04:11:52 -0700, I wrote: >peal peel .... oh, well. Jon
From: Mel on 24 Jun 2010 08:15 David Brown wrote: > I suppose it all depends on what you define as "hobbyist". > > Finding a source for the documentation, and buying it (assuming these > manuals were priced similarly to a lot of other comparable technical > information) would take a lot of effort and money. > > It may also be as simple as you being lucky in finding these prototype > boards from IBM. Imagine a hobbyist who hadn't found out about these > and wanted to make an ISA card. Active (must have been them, can't imagine where else I'd have got them then) sold boards with the appropriate edge connector and traces for typical interface chips -- then a huge wire-wrap area. Personal Computer Technical Reference had full schematics for the PC side of the interface. Mine was off the shelf from a bookstore in Boston. Admitted, the farther from MIT, the harder they were to find. They were more scarce in Toronto. And my first MIDI adaptor was a kit from a technically-aware hole in the wall called Computer Parts Galore. Mel.
From: David Brown on 24 Jun 2010 09:35 On 24/06/2010 13:11, Jon Kirwan wrote: > On Thu, 24 Jun 2010 11:07:50 +0200, David Brown > <david(a)westcontrol.removethisbit.com> wrote: > >> <snip> >> Finding a source for the documentation, and buying it (assuming these >> manuals were priced similarly to a lot of other comparable technical >> information) would take a lot of effort and money. > > It wasn't hard. I'm not certain anymore, but I believe I > first heard about the information either in a magazine or > through the materials received when purchasing. I do > remember getting a price and part number to order from IBM, > by phone, and then simply writing a check and mailing it off. > It wasn't a lot of money, either. Especially considering > that the IBM PC/AT, 6MHz and 20Mb hard drive, was priced at > $5495, memory serving. If you could find a way to peal that > much out of your wallet, the manuals weren't even on the > radar scope. > I guess it is this more than anything else that puts ISA out of the range of hobbyists to my mind - you don't mess around with putting home-made cards into a $5500 computer unless you are happy to risk damaging it, or you are /very/ confident of your abilities. Either way, you are not a hobbyist. Hobbyists who wanted to connect a card to a PC gave them an RS-232 interface or a parallel port connection - just like these days they give them a USB connection or an Ethernet port (or possibly a RS-232 connection).
From: Grant Edwards on 24 Jun 2010 10:06 On 2010-06-23, Jon Kirwan <jonk(a)infinitefactors.org> wrote: >>Swapping in a 2.00MHz oscillator for a 1.843MHz oscillator on a PCI >>card requires _exactly_the_same_ skills as doing it on an ISA card. > > Not so. I'm looking right now at two such cards, one ISA and > one PCI. The ISA board has a large, socketed crystal module. > The PCI a tiny, SMT unit. That's a characteristic of those two particular boards. It's not a characteristic of ISA vs. PCI bus. > The skills required for modifying one is much different (and the tool > tips required, too.) It _may_ be the case, but not necessarily so as > these two boards easily illustrate to me. Replacing an SMT oscillator is really quite trivial. It's easier than replacing the non-socketed, through-hole parts on most ISA boards. -- Grant Edwards grant.b.edwards Yow! ... the HIGHWAY is at made out of LIME JELLO and gmail.com my HONDA is a barbequeued OYSTER! Yum!
From: Jon Kirwan on 24 Jun 2010 19:22
On Thu, 24 Jun 2010 14:06:05 +0000 (UTC), Grant Edwards <invalid(a)invalid.invalid> wrote: >On 2010-06-23, Jon Kirwan <jonk(a)infinitefactors.org> wrote: > >>>Swapping in a 2.00MHz oscillator for a 1.843MHz oscillator on a PCI >>>card requires _exactly_the_same_ skills as doing it on an ISA card. >> >> Not so. I'm looking right now at two such cards, one ISA and >> one PCI. The ISA board has a large, socketed crystal module. >> The PCI a tiny, SMT unit. > >That's a characteristic of those two particular boards. It's not a >characteristic of ISA vs. PCI bus. Which doesn't injur my point at all. >> The skills required for modifying one is much different (and the tool >> tips required, too.) It _may_ be the case, but not necessarily so as >> these two boards easily illustrate to me. > >Replacing an SMT oscillator is really quite trivial. It's easier than >replacing the non-socketed, through-hole parts on most ISA boards. With good tools for SMT available. I recently _did_ after 30 years finally purchase my very first fine tip for attempting such work. But for 30 years, this would have been a disaster had I tried, while through hole is something I am quite long since used to handling. Of course, none of this is about my earlier point regarding ISA vs PCI for hobbyists. Itself, of course, nothing about the earlier thread. So we are far out to field now. Jon |