what is this?

ganonbanned · Post by **ganonbanned** » Sat Sep 01, 2007 4:37 pm

I was going through my mac stuff today, and found this... I bought this all in a lot, and I remember wondering what this was a while ago to. I have a lot of old mac stuff but this looks somewhat new, maybe some kind of converter? idk, hopefully someone can help. sorry if the pics are huge.

Reaperman@home · Post by **Reaperman@home** » Sat Sep 01, 2007 4:41 pm

it's definitely parallel with 'centronics' ends on them.
this site here mentions that centronics and IEEE1284 were the same physical shape but the pins had different uses in each. Perhaps this just switches some pins around.

seems like there's something I'm missing, though. Every so often I dig one of these out of 'the dungeon' at work, attached to some ancient yellowed printer. I puzzle over its use for a couple seconds before throwing it behind something. Whatever it was was very common, but I'm just a little too young to have needed one...for whatever.

ganonbanned · Post by **ganonbanned** » Sat Sep 01, 2007 5:02 pm

Reaperman@home wrote:it's definitely parallel with 'centronics' ends on them.
this site here mentions that centronics and IEEE1284 were the same physical shape but the pins had different uses in each. Perhaps this just switches some pins around.

seems like there's something I'm missing, though. Every so often I dig one of these out of 'the dungeon' at work, attached to some ancient yellowed printer. I puzzle over its use for a couple seconds before throwing it behind something. Whatever it was was very common, but I'm just a little too young to have needed one...for whatever.

Thanks!! I thought it might be something like that, or an adaptor or something. They pulled hundreds of outdated PC's out of the school basement, and I got a lot of stuff. this just happened to be in a box.

Electric Rain · Post by **Electric Rain** » Sat Sep 01, 2007 5:05 pm

Wow... yeah, it's a Centronics cable alright... it appears to simply be an extender... but who would make a Centronics extender when they could just use a DB-25 extender on the other end?

Post by **bicostp** » Sat Sep 01, 2007 5:34 pm

Reaperman@home wrote:it's definitely parallel with 'centronics' ends on them.

Wrong.

It's a SCSI terminator, made of a bank of resistors. You put it on the end of your SCSI bus to stop signals from reflecting and messing up data transfer. If the machine you were working on has no internal hard drive (namely a Plus or an SE with 2 floppy drives), you would put one at both ends. (Hence the double-sidedness.) If your machine had internal termination you only put one terminator on, and it would go on the end of the chain. If you had a Mac IIfx you had to use a special black terminator for some reason.

Confused? I don't blame you. SCSI is dark majik.

Believe me, I grew up with Macs. That's a SCSI terminator, it has nothing to do with PC parallel ports.

Reaperman@home · Post by **Reaperman@home** » Sat Sep 01, 2007 7:24 pm

bicostp wrote:
Reaperman@home wrote:it's definitely parallel with 'centronics' ends on them.
Wrong.

It's a SCSI terminator

that sounds much more likely. If I had to guess without looking, the ones at work attached to the printers in storage were probably gender changers, which this unit doesn't do.
Counting the pins on this, it is centronics-50 (scsi) rather than centronics-36 (parallel)

odd that a school would be using scsi.

Post by **Black Six** » Sat Sep 01, 2007 9:02 pm

Reaperman@home wrote:odd that a school would be using scsi.

Not really. Apple computers used SCSI almost exclusively until the PowerPC era I believe. I have a Performa 6400 sitting next to me right now that uses SCSI for one hard drive and the CD and IDE for a second hard drive, so that's about the time they began switching (~1996). Yeah they were more expensive, but Apple used them because they were faster and more reliable that IDE at the time. Eventually PATA caught up in the speed department (not completely, but close enough) and were so much cheaper that it made sense to switch in all but the highest performing machines (which is why many servers today still use SCSI).

Post by **bicostp** » Sat Sep 01, 2007 9:30 pm

I think the non-beige G3 class Macs (Powerbook G3, the first iMac, and the blue tower) were the first generation to drop SCSI support. My Power Mac 7600 has a SCSI jack, even though the internal parts are all IDE. Ah SCSI, those were confusing times... (Between ID numbers, wiring weirdness, termination... darn kids and your USB plug-and-play hard drives... You have no idea how easy you have it.)

Maybe tomorrow I can take a picture of how it's rigged up.

Post by **Black Six** » Sun Sep 02, 2007 6:49 am

bicostp wrote:I think the non-beige G3 class Macs (Powerbook G3, the first iMac, and the blue tower) were the first generation to drop SCSI support. My Power Mac 7600 has a SCSI jack, even though the internal parts are all IDE. Ah SCSI, those were confusing times... (Between ID numbers, wiring weirdness, termination... darn kids and your USB plug-and-play hard drives... You have no idea how easy you have it.)

Maybe tomorrow I can take a picture of how it's rigged up.

Woohoo for jumper pins! It's always fun when you come across an old hard drive that doesn't have a pin diagram on it and you have to look all over the web to make sure the jumper settings are good before you can plug it in and find out what's on it.

Post by **bicostp** » Sun Sep 02, 2007 9:14 am

Black Six wrote:Woohoo for jumper pins! It's always fun when you come across an old hard drive that doesn't have a pin diagram on it and you have to look all over the web to make sure the jumper settings are good before you can plug it in and find out what's on it.

Tell me about it! I pulled the hard drive out of my SE/30 a couple weeks ago to copy the files off it, and it had no jumper indicators. (It's just the stock 80 MB drive.) It took some fiddling to make my Power Mac happy with it. Fun!

NEVER play with the inside of a classic style all-in-one Mac if you don't know what you're doing! One finger in the wrong place = dead.

Post by **benheck** » Sun Sep 02, 2007 9:19 am

I vote SCSI terminator 2. (Hasta la Vista). Mac was all SCSI until the mid-90's. Well before they went Intel CPU and become Macs in OS only (ha ha I went there)

There's a project, unless somebody's done it. Put OSX on a PC!

Harshboy · Post by **Harshboy** » Sun Sep 02, 2007 9:27 am

benheck wrote:Put OSX on a PC!

It's been done...hell, I did it like 2 years ago

Kyo · Post by **Kyo** » Sun Sep 02, 2007 10:01 am

aren't there official versions for PCs now?

lifeisbetterwithketchup · Sun Sep 02, 2007 11:43 am

Kyo wrote:aren't there official versions for PCs now?

No. Apple would never let their OS be on non-Apple hardware. Apple's hardware and software have always worked together to form an Apple product. Without that synergy, Apple's OS wouldn't look so great anymore (it couldn't be tailored to specific hardware).

Post by **bicostp** » Sun Sep 02, 2007 12:03 pm

Kyo wrote:aren't there official versions for PCs now?

Nope. In fact the EULA forbids running it on non-Apple hardware.

I think they do this for 2 reasons:

1. So they know what the computers it will run on have for hardware, and can optimize it accordingly.

2. People would rush out and buy a Dell or a Gateway, put OS X on it, and then complain to Apple because it doesn't work right.

Really aside from the OS there's no difference between a Mac and a generic x86 compatible anymore. I just think it's amusing that people still don't understand that fact, and automatically dismiss it as "overpriced crap", then in the same breath go crazy over the new $3000 gaming PC with an AMD processor.