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SASI drive replacement

C

curbie

Experienced Member
Joined
Mar 23, 2019
Messages
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Eventually, I'm going to get this little AM1000 running, then the parade of “WHAT Ifs'” will turn to the disk drive, “WHAT IF” the drive does or does not work, “WHAT IF” the OS does or does not exist, “WHAT IF” I didn't think of all the “WHAT Ifs'”, blaa, blaa, blaa.

Regardless, for potential backup of the OS, and a solid drive to build on going forward I'm going to need a SASI drive replacement. I've seen some SASI to IDE or SD Card devices, which look interesting, I can't be the first to go after this issue. Anybody have a suggestion?

curbie
 
Al,

To start with, my AM1000 has a 50pin SASI port going to the 50 pin port on a XEBEC (IIRC a 14??) with two ribbon cables going to the drive, one 34 pin, and one 20pin ribbon cable (maybe the SASI to MFM adapter board you referred to?). It seems that the board in that URL, is for a PC computer, and could be useful in retrieving data from a drive, by am confused how this might replace a drive. Do you have any experience with that board?

I found a board on another site that seems to replace both XEBEC and drive with a SD memory card, but being on double secret probation and out of SPAM caution, I don't want post a link for comment, until I figure out what is proper out here.
 
Hi jon,

that is the type of device that i was referring to, but where do i buy one?
 
SteveH said:
Try searching for SCSI2SD, you'll find them on eBay and Amazon for starters.

I got a v5.1 model from AmigaKit http://amigakit.amiga.store/product_info.php?products_id=1264
Worked great on my LSI Octopus to replace a Xebec controller plus Rodime MFM drive - that is until I blew the motherboard drive logic (soon to be my next project)
Click to expand...
how did the SCSI2SD preform compared to the original disk drive? was the original disk drive or XEBEC bad?
 
curbie said:
how did the SCSI2SD preform compared to the original disk drive? was the original disk drive or XEBEC bad?
Click to expand...

Although I didn’t perform any speed tests, the SCSI2SD was certainly quicker than the original MFM drive. Whilst there wasn’t anything wrong with the Xebec controller, the MFM drive was showing its age – occasionally it would just power down or most often would throw up read/seek errors after being powered on for an hour or more.

My setup consists of: LSI Octopus (8088 + Z80B) computer, Xebec S1410A controller and Rodime RO204 20Mb MFM drive

Using the SCSI2SD I was able to emulate any hard drive size that the Octopus supported and produce partitions for Concurrent CP/M-86, MS-DOS 2, ELSIE and Tape streamer support. The latter 2 were of little use to me, not having the ELSIE o/s or tape streamer hardware.

All in, it works extremely well – quick, low power consumption and less heat produced, easy to switch out SD cards to backup or copy hard drive images. The only downsides are that different size hard drive images do require re-flashing the SCSI2SD config and you don’t get the classic sound of heads seeking back n forth. Also, the versions of Winchester Format and Partition program I have did hiccup during the format process, but worked fine if specifying a re-partition instead – go figure!
 
Just be careful here. I think what Al was trying to point out is that SASI isn't exactly a strict subset of SCSI, so it's possible that it may not work 100% with the Alpha Micro. No way to know until you try it, of course.
 
CLASSIC,

i hear you and agree, technically, SCSI-1 is fully implemented sub-set of SASI, just depends how technical the SCSI2SD is to whether SASI-1 is even partially or fully implemented. but from reading JonB's thread i have hope, the real selling point for me comes from reading JonB's entire thread, linked to by the URL he posted above, along with the possibility of the developer either have done an Alpha Micro before OR working with the developer to tune this SCSI2SD to function with the Alpha Micro. sounds like a fun project in and of itself.

it's only $98 bucks, and some time, just like the eproms, UV easer, and eprom programmer I just bought, I know I'm just chasing a theory and there is no guarantee that a replacement boot prom will solve the boot-up issue, just another step in isolating the issue... the last step, maybe, maybe not?

same thing with the SCSI2SD, maybe, it will replace the SASI disk drive, maybe not? What i do know, is that i'm going the have to chase the best options to their conclusions, and if they don't solve the issue, i'll try the chase next best option, I find that techs that don't enjoy the journey, sometimes loss patience before reaching the destination.
i don't like tv, golf, or cards... i need something to fill my days.

curbie
 
curbie said:
steve,

not on Amazon, but found them here: https://store.inertialcomputing.com/SCSI2SD-v6-p/scsi2sd-v6-revf.htm. got one on the way.
one person's recommendation means more to me than 10 sales pitches. thanks.

curbie

if you are ever looking to sell that XEBEC, let me know.
Click to expand...


Just had another look on Amazon and couldn't find one - I stand corrected.

Keep us informed of your progress once you've got it. If you have problems, someone here should be able to help, plus the designer of the card is approachable (and has helped others on this forum).

For the moment the Xebec is my fall back card, but I’ll let you know if I decide to sell it.
 
steve,

I wasn't looking to correct anyone, just making sure the path is clear on this thread for the next person, because i'm easily confused.

over 17 years, with several hundred Alpha Micro's on monthly maintenance contract, I recall only one XEBEC hardware failure, and that was in Florida "the lighting capital", those XEBEC controller's were as solid as they come.
It's not good enough to get this little guy up and running after 50 years, i want to collect enough spares to hopefully keep it running for another 50. the last running Alpha Micro has a nice ring.

curbie
 
curbie said:
steve,

not on Amazon, but found them here: https://store.inertialcomputing.com/SCSI2SD-v6-p/scsi2sd-v6-revf.htm. got one on the way.
one person's recommendation means more to me than 10 sales pitches. thanks.

curbie

if you are ever looking to sell that XEBEC, let me know.
Click to expand...

Now I'm back on this SCSI2SD in case I can get my drive going I'll need a stable solution, I saw my old post and needed to correct it, in preparing for this SCSI2SD last time, the people at SCSI2SD recommended version 5.1 Not version 6 due to the age of the Alpha, they felt version 5.1 was better suited so that’s what I bought.

Back in the day I wrote a few drivers for interfaces and disk drives for the Alpha, and being a pack rat I still have the source code, so with a little luck, I should get that going eventually.
 
My concluding post to this thread, thanks to members on this board, and the boot drive they setup for me, my little AM1000 is up and running well now.

After two additional repair cycles, (schematics and logic probe, find part online and order it then wait for it to show up, install then run through paces), this Alpha now “feels” fine, and hasn’t popped a single parity error since the last fix over two weeks ago.

So now I’m back at the scsi2sd, it doesn’t seem possible that scsi2sd has been out there that long, gone though that many revisions, has such a following, gets good reviews, and still has basic flaws. So I bought another identical Maxtor LXT-213SY as my existing boot drive, and low and behold… the exact same 255 block logical unit problem as a secondary drive as with the scsi2sd, smells like a Alpha software bomb!

I’m going to carry on trying to get the Alpha and scsi2sd to play nice, and/or chasing a viable backup scheme, but those updates won’t be on this thread, maybe on my “SASI drive replacement” thread, or maybe on a new Alpha backup thread depending on what I find?


Thanks to ALL that helped me get this far.


Curbie
 
My PDP-11 originally also had a XEBEC disk formatter connected to the controller. After some ups and downs I finally managed to have the SCSI2SD talk correctly to the Plessey disk controller. However there have been some pitfalls. Firstly I only was successful with the SCIS2SD V5.0 but not with the V5.1 I have no explanation why this is so. I have both versions. I also contacted Michael but he did not have any explanation either. Long story short, I just bought another V5.0. In addition in my case the PDP-11 expected the disk to be formatted with 256bytes sectors. Although you can tell SCSI2SD that sector size is 256bytes it will not translate the block numbers to place two 256bytes sectors in a 512byte SD-Card block. Here is some more information

https://www.5volts.ch/posts/plessey/

Peter
 
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