Still Crazy

971018 - Differential Story

Back in 1997, hard drives were not so cheap here in Japan. New hard drive of 1G capacity costs about JY10,000. As a matter of fact I could not pay such money for SCSI hard drives. According to my master of MCA, used 5" full height drives were relatively cheap to get. He wrote that he sometimes got 1G drive for JY1,000 in used PC market. OK, that was the way I liked.

18 Oct

As usually, trolled around junk shops. Found three ST42400ND at a shop. A clerk said they were defective and their testing system could not detect them. I had taught by the master of MCA that the last letter "D" in Seagate drive meant "Differential". Paid JY3,000 for three drives. Ordered Rancho single-differential converter to US (it cost me another JY5,000, MAD level increased one step higher).

Nov. date unknown

Got single-differential converters from hi-tech inc. One was Rancho's converter and the other was labeled as "Juke Box". Rancho converter could be used in bi-directional, from differential drive to single-ended usual adapter and/or from single -ended drive to differential adapter. Juke Box is a tiny card to be connected to differential hard drive directly.

Opened up my "Grandma", connected the Rancho off from short cached SCSI 2/A with yellow DIP terminator (of course the terminator was pulled off) after the small IML drive, and then connected a ST42400ND to Rancho differential end. Hey-ho, 2G capacity would be provided for me with Rancho converter. "Power on!", pushed the main SW. "Go baby go, go. Go baby go go...?" Charming error code was displayed on the LED panel (don't remember it). Tried various combination of jumper blocks on the Rancho card. No lucks... Pulled off the Rancho card and powered up 5580.

SCSI drive was not detected by the system. 5580 warned me that Spock SCSI is defective!

The short, cached SCSI /A that I used for the test was known to be capable to handle IML drive >1G. And that was the only one I had back then. I had not yet tried it with a usual single-ended narrow drive larger than 1G (because I had not such a drive. All of my 3.5" SCSI drives were below 500MB). Yes I had some of bigger drives but they were all 5" full height shape made of DEC, Micropolise and Fujitsu. What the h*ll happened there. I examined short Spock to every inch with my ohm meter and found that a very little black square chip was defective. Same part used in 16bit SCSI card had electrical connection (sorry I don't know how to say call it) between both end, but the one in 32bit Spock had no connections. A needle of my ohm meter deflected outer ward. The part might was supposed to be a FUSE with it's silk marking "F1". What kind of fuse it was? I asked to the Forum and got an answer that it might be a part so called "polyswitch". Few days latter I got similar kind of tiny chip and used it to replace the burnt one. Bingo! Specification of the chip I bought was bit different from original part but it was functional and revived my precious love.

Oh, well, I should talk about Rancho. As a matter of fact I don't remember how I got rid out of the trouble. But Rancho converter securely drove ST42400NDs. It had been sat in my 5580 for about 3 years with a ST42400ND. I also got some differential drives latter. HP, Sequant (probably HP OEM) and Seagate. Most of them were donated to used PC Parts forum.

Someday in 2000, I happened to see funny drive cages pulled off from unknown server machine at a garage shop. I could just recognize markings "IBM", "DFxx" through punching holes of the cage. They were not slim height drives so I assumed they should be DFHS S4F (Single Ended 50pin Fast) or S4F (Single Ended 68-pin Fast/Wide). I Paid JY3.000 for 3 assembly of cages and drives. Back at home, disassembled the cages, saw the labels on the drives saying "DFHS S4E" Grrr... they were actually First/Wide drives but... Differential.

Apr 2001

Read message by Dan that he wanted to sell differential corvette. The part number was same with the one supposed to be functional on PS/2 (according to Louis' page). Paid for it through PayPal. Received a Differential First Wide SCSI II /A. I'm ashamed. I have not yet checked it to drive DFHS S4Es in my 95.

Japanese Lesson #1

go go: "5" is "go" in Japanese. "55" is "gojyu-go" (say, 10 is "jyuu").
Mathematically "55" should be pronounced as "gojyuu-go".
I usually call it as "PS go-go"
I don't know how IBM called PS/55, PS fifty five, PS gojyuu-go, PS go-go...
But anyway... Go baby go, go. GO baby go go go go. Jophny B. Good...

I bet Sony PlayStation will never reach to "55" and PS/55 will always be high above from it.

Content created and/or collected by:
Louis Ohland, Peter Wendt, William Walsh, David Beem, Tatsuo Sunagawa, Jim Shorney, Tim Clarke, Kevin Bowling, Tomáš Slavotínek, and many others.

Ardent Tool of Capitalism - MAD Edition! is maintained by Tomáš Slavotínek.
Last update: 13 Sep 2021 - Changes & Credits | Legal Info & Contact