test-drb April 2001

test-drb@ccmp.vtda.org

251 participants
669 discussions

by optimus＠canit.se

As we all know, Ethernet was only running at 3 Mbit in the early days. When was the move to 10 Mbit done and is 10Mb Ethernet backwards compatible? Also, were there any Ethernet controllers back in the old days, or what kind of interfacing did old Ethernet capable equipment such as the SUN 1 or DECNA use? -- En ligne avec Thor 2.6a. Was ist ein Erwachsener? Ein Kind, das vom Alter aufgepumpt ist. --- Simone de Beauvoir

24 years

IBM's PGA Adapter

by mcguire＠neurotica.com

On April 22, jpero(a)sympatico.ca wrote: > > Hi. Can anybody provide me with some info on the IBM PGA/PGC adapters for > > the IBM PC/XT systems? > > > > I heard that it is one of the first video adapters with on-board transform > > capabilities, and that it is very ahead of its time. Can anyone please > > elaborate? > > Also, where can I get some pictures, and is it still available for > > purchase? > > Half-half acceleration due to built in CPU and can compute arcs, > lines etc for cad work I think. > > But I know PGA is grossly unusual design and unrealistic cost kept it > from very common plus it requires non-standard PGA monitor to go with > it. Cost was about 5,000 I think. > > BTW, it is 3 boards package and monitor. Saw both monitor and card > set but not in action. If memory serves, the PGA had an 8085 processor on it. Interesting use of an otherwise general-purpose microprocessor. <flame bait> Indeed, an XT-class system with a PGA had a better processor on its video board than it did on its motherboard. </flame bait> -Dave McGuire

24 years

Using a 1.44MB 3.5inch floppy on an old controller

by mbbrutman＠chartermi.net

I have a few PCjrs running around, and I've often thought of either adding 3.5" drives to them, or replacing the standard 5.25" drive with 3.5" drives. The controller only supports double density data rates (250?), so I'm limited to 720KB 3.5" drives. These are getting hard to find. I connected a new 1.44MB drive to the controller, and behold, it worked! (With double density media of course.) The machine booted from the diskette (which was created from a 360kb image prepared on a Linux machine), and it also ran diagnostics. So now I'm confused - why did it work? Does the modern 1.44MB drive sense that the controller is only sending data at 250KHz rate? If so, how is it doing the sensing? (The reduced write-current pin (2) isn't being used - I verified that with a meter.) Thanks, Mike

24 years

VAX 6000 3-phase conversion (was: Re: Three Phase)

by ajp166＠bellatlantic.net

From: Clint Wolff (VAX collector) <vaxman(a)qwest.net> >The cages I've seen are made from an expensive copper screen, >like window screen, but they are for doing FCC interference >measurements, not shielding. I can get 1/2 inch square fencing >from the look home improvement center, but it is galvanized and >quite a bit coarser... > >Comments? First a faraday cage to run a vax is foolish. The FCC notice refered to is basically a hint about whose reponseability it is to fix RFI problems should they occur. Often it's not a problem save for at point blank range. RE: galvanized screening vs fine copper screening. If you cant do it right dont bother. As the holes get larger and the resistivity increases the attenuation decreases. Also as the holes get bigger the frequency at which the screen becomes RF transparent also gets lower. So to get an effective faraday screen fine copper screening with well bonded (often soldered) joints and a door that has RF tight joints are used. Also any wires that enter or leave have to be bypassed to avoid it becomming a leakage path in either direction. I participated in building one and it's a lot of work and after testing to find RF leaks. At the other extreme a cage of .500 galvanized will have effect but the effect is far more limited. to prove it take a roll and make a mini cage large anough to hold a battery AM/FM radio and see what I can hear >from inside it. Then take a tube and coat it with aluminum foil and try it with the same radio. You will also find it very difficult to solder or otherwise effectively bond the joints of a galvanized wire cage. Last item: The average system (even a PDP-8) will be much better in the RFI derby if all the covers are on and the correct cables are used. The later smaller one box systems are fairly decent if the case is metal and all the screws/hardware are in place. The killer items for RFI are SCSI cables, external disks that used any unshielded cables (BC05s come to mind) or monitors that used shielded cables but are incorrectly terminated. RS232 wires that do not use an external shield can be a path to propagate noise out of and otherwise tolerable box as well. Worst offender awards: TRS80 with EI... ghastly both radiating and affected by nearby transmitters. (1w 144mhz ht at 4ft would crash the average TRS80). Some of the Apple][s Early S100s with non-stripline and unterminated busses (altair!!!!). SBCs, no case at all most often. Many of the early all plastic cased (no internal conductive spray coat) with no internal shielding systems. Many (most) CRTs that are not metal boxed internally are noisy. Allison

24 years

What's a Mag Card II?

by mmcfadden＠cmh.edu

The microbiology lab where I worked kept a different card with each type of pathology report on them. The operator would enter the sample information into a "canned" document, and then could append any additional comments. These machines were real popular in the early 1970's for thesis typing and routine reports. You could put a chapter or a section on an individual card. Our secretary in graduate school had one and kept all the routine documents on individual cards. You wanted to requisition something she put in the requisition mag card, filled in the blanks and printed out the requisition. The unit had a IBM Selectric style printer as an output device. Mike mmcfadden(a)cmh.edu

24 years

Amstrad PPC640

by daverogers90＠hotmail.com

Hi my name is Dave i live in NewZealand i have been givern a PPC640 wich goes but it wants a start up disc if u have one could you please send a copy of it to me on brav(a)zfree.co.nz i would love to crank it up.

24 years

(3) Northstars + DiscJockey to rescue in Bothell, WA

by jfoust＠threedee.com

I'm trying to reduce the size and increase the sensibility of my collection, so I'll pass this one to the list... please contact him, not me. - John >From: "Wayne Gilmore" <wayneg(a)aa.net> >To: "John Foust" <jfoust(a)threedee.com> >Subject: Re: Old Computers >Date: Sat, 21 Apr 2001 13:11:57 -0700 >X-Mailer: Microsoft Outlook Express 5.00.2615.200 > >Hi again John, >I am located in Bothell, Washington. A few miles north of Seattle. >Wayne > >----- Original Message ----- >From: John Foust <jfoust(a)threedee.com> >To: Wayne Gilmore <wayneg2(a)mindspring.com> >Sent: Saturday, April 21, 2001 12:35 PM >Subject: Re: Old Computers > > >> At 12:16 PM 4/21/01 -0700, you wrote: >> >Hi. I have 3 northstar computers that I bought new and used for >business and as a personal pc before pc's.... yuk.. Also have a Morrow >Discjokey system that worked with it. I'd like to donate all... Manuals and >anything else that I have had to someone that wants them. Help >> >Thanks >> >Wayne Gilmore >> >> Wonderful! Where are you located? >> >> - John >>

24 years

(3) Northstars + DiscJockey to rescue in Bothell, WA

by jfoust＠threedee.com

24 years

L@@K! RARE -- 2 EBAY SELLERS CONVICTED and 1 on the run....Another nice ebay ("epay") story...

by claudew＠videotron.ca

Sheeesh...not surprised....at all.... http://dailynews.yahoo.com/h/nm/20010417/wr/crime_ebay_dc_1.html I will continue to boycott this place as both a potential seller and buyer. Claude Canuk Computer Collector http://computer_collector.tripod.com

24 years

VIC-20

by LFessen106＠aol.com

In a message dated 4/23/01 9:00:28 AM Eastern Daylight Time, r_beaudry(a)hotmail.com writes: > > I have an 8K cartridge, and I believe also a 16K cartridge gathering dust on > my shelves. Email me your address, and I'll ship them off to you ... No > guarantees that they work, but they're free :-) > I would love to have one of these myself.. Let me know if there are any "extras" floating around! -Linc Fessenden The nice thing about Windows is - It does not just crash, it displays a dialog box and lets you press 'OK' first.

24 years

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test-drb April 2001