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by robespierre
Mon Mar 27, 2017 12:44 am
Forum: SGI: Discussion
Topic: Hardware is Cheap, Programmers are Expensive
Replies: 14
Views: 275

Re: Hardware is Cheap, Programmers are Expensive

A DBA is just a specialized developer (who conventionally has "ownership" over the database files, so can be mistakenly seen as just Ops instead of a designer). But (in theory) their training is more standardized than typical developers. Is there any specific theory that you can rely on a ...
by robespierre
Sun Mar 26, 2017 11:44 pm
Forum: SGI: Discussion
Topic: Hardware is Cheap, Programmers are Expensive
Replies: 14
Views: 275

Re: Hardware is Cheap, Programmers are Expensive

Programmers working in HPC have always spent more effort to ensure high quality and performance, including using esoteric languages and "old-fashioned" development methodologies. The reason is that when you need the highest performance possible, "it will be faster and cheaper on next ...
by robespierre
Thu Mar 23, 2017 12:46 pm
Forum: Hardware For Sale/Trade
Topic: Free: SGI 20" CRT Trinitron Monitor GDM-20E21 - New York
Replies: 6
Views: 333

Re: Free: SGI 20" CRT Trinitron Monitor GDM-20E21 - New York

On very old televisions, repair shops sometimes attached devices called "Brighteners" that increased the filament voltage, in order to fix a dim picture. They make the cathode run hotter, which could conceivably shorten its life. But these devices were obsolete by the 1980s when sophistica...
by robespierre
Wed Mar 22, 2017 3:34 pm
Forum: SGI: Hardware
Topic: No graphics out from Indigo2
Replies: 24
Views: 364

Re: No graphics out from Indigo2

It's a Seagate Hawk model ST31200N. All I have on the side is a small L-shaped ribbon cable that connects between a six-pin header on the drive and a rectangular black connector wired to the drive sled. That is a dedicated jumper block (J5) for setting the drive's SCSI ID. It is wired to a cable so...
by robespierre
Wed Mar 22, 2017 12:57 am
Forum: Apple
Topic: The Problem with Apple
Replies: 85
Views: 1563

Re: The Problem with Apple

Yes, I agree with all the above. One other problem with leakage currents is that they interfere with capacitive touch sensing, leading to problems with tablets and the new multitouch notebook pointing devices.
by robespierre
Tue Mar 21, 2017 10:49 pm
Forum: SGI: Hardware
Topic: Indigo² sound board w/blown caps
Replies: 5
Views: 155

Re: Indigo² sound board w/blown caps

As far as I know, there is no failure mechanism that is age-related. It's usually the opposite: they fail with infant mortality when power is first applied. The way these are made is by printing thin layers of tantalum and MnO2, then applying a forming voltage, much like an aluminum electrolytic cap...
by robespierre
Tue Mar 21, 2017 7:49 pm
Forum: SGI: Hardware
Topic: No graphics out from Indigo2
Replies: 24
Views: 364

Re: No graphics out from Indigo2

That is GR3-Elan. Does it cause the same problems when moved to the other GIO64 slots?
by robespierre
Tue Mar 21, 2017 5:57 am
Forum: Getting Started, Documentation, Tips & Tricks
Topic: New haul: 2 x Octanes, Q about TMEZZ TRAM module upgrades
Replies: 7
Views: 288

Re: New haul: 2 x Octanes, Q about TMEZZ TRAM module upgrades

That PCI card is called the CadDuo, it allowed two simultaneous users.
The processor module could have a bent connector or socket, as I recall the wider dual-CPU ones were under more mechanical stress.
by robespierre
Mon Mar 20, 2017 10:17 pm
Forum: SGI: Hardware
Topic: Dallas chips
Replies: 30
Views: 399

Re: Dallas chips

praetor242 wrote:I don't _think_ that affects the functionality of the machine, because in Irix 6.5.x it's recommended you setup tzdata and ntp.

That's a non-sequitur. The timezone and date are set in the NVRAM; they have squat-all to do with the OS.
by robespierre
Mon Mar 20, 2017 5:41 pm
Forum: SGI: Hardware
Topic: Indigo² sound board w/blown caps
Replies: 5
Views: 155

Re: Indigo² sound board w/blown caps

OK, I got out the calipers. The tantalum caps are 2917 (Imperial) / 7343 (metric) case size, and 2.8 or 3.1mm height. This is called 'D' case by the manufacturers. I don't know the original caps' ESR. Tantalums this size are made in a wide range, from 40 to 900 mOhm. But with polymers you have basic...
by robespierre
Mon Mar 20, 2017 2:06 pm
Forum: SGI: Hardware
Topic: Indigo² sound board w/blown caps
Replies: 5
Views: 155

Re: Indigo² sound board w/blown caps

I've seen this happen and heard of it happening to others. These are tantalum MnO2 caps, which blow up if (1) Their voltage rating is exceeded; or (2) they are exposed to more than a couple volts in reverse. This should never happen, so the failure indicates that something else has gone wrong. The t...
by robespierre
Fri Mar 17, 2017 5:12 pm
Forum: SGI: Hardware
Topic: No graphics out from Indigo2
Replies: 24
Views: 364

Re: No graphics out from Indigo2

The serial ports are compatible with RS232 and use it by default. RS422 is an option, but it needs to be specially enabled by software. A mac serial printer cable will work as a null-modem, and you can then plug it into a USB serial adapter like a Keyspan 28X. That's what I use.
by robespierre
Fri Mar 17, 2017 4:37 pm
Forum: SGI: Hardware
Topic: No graphics out from Indigo2
Replies: 24
Views: 364

Re: No graphics out from Indigo2

SCSI drives do not necessarily spin up until they receive a START UNIT command from the host. It was commonly a jumpered option in case autostart was desired. The "ribbon cable next to the CPU board" is the internal SCSI connection. The memory will only be recognized if it is in the correc...
by robespierre
Tue Mar 14, 2017 12:37 pm
Forum: SGI: Hardware
Topic: No graphics out from Indigo2
Replies: 24
Views: 364

Re: No video out from Indigo2

The light turns yellow during self-test. When the test passes, it turns to green.
by robespierre
Mon Mar 13, 2017 10:08 am
Forum: Everything Else
Topic: What extremely rare (non-prototype) computers do you wish you could find?
Replies: 62
Views: 1029

Re: What extremely rare (non-prototype) computers do you wish you could find?

I'd anticipate that picking up a 3-button ADB mouse (they exist!) might help with that last, though I've not tried it. A3.jpg There is support for 3-button mice: the manual mentions the Logitech MouseMan. The only one I've seen is the (optical) Mouse Systems A/3, and finding them is not easy. It mi...

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