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Xebec SASI controller utilities disk image for Apple II needed

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Klotho

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Jan 10, 2023
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Hi,
I'm a vintage computer collector from Germany and new to this forum. Recently, I acquired some Apple II+/IIes and with them came a Xebec SASI host adapter and a huge hard disk. From browsing the web, I found that apparently Xebec sold kits consisting of the host adapter for an Apple II/II+/IIe plus an external controller PCB to turn a dumb MFM hard disk drive into a SASI HDD – at least I found a Xebec manual describing such a kit. Some German company probably called Rothahn seems to have used those kits together with a compartment and a huge full-height BASF 5 ¼” hard disk with whopping 21 MB to sell them as complete HDD stations for the Apple II – I even got a German manual for it.
Unfortunately, booting from this BASF HDD didn’t work out of the box so I have to assume that at least the data one that HDD might get corrupted over the last 40 year - or the drive is gone, although it still spins up. I’d like to try to revive the station by giving the BASF drive a low-level format or by replacing it with another working MFM drive (which I have) but I couldn’t find an image of the necessary Xebec utilities disk anywhere on the usual websites. According to the two manuals I have a disk version names “XEBEC Apple Pascal 1.1” for the Pascal OS as well as an equivalent utility disk version for DOS 3.3 and for CP/M 2.20B must have existed. If anyone out there would be able to provide images for one (or all at best) of those utility disks, I would be very happy indeed 😉…
 
I'll bet the FirstClass Peripherals 'Sider' software will work with that setup. That should be available on the web.
 
I knew that those Xebec host adapters were also used by the Sider HDDs - but from want I found out, they were apparently using a different ROM on the host adapter for each hard disk type the system was shipped with the drive geometry in that ROM. I found the Sider manuals on the web and from what I saw there, the Sider tools read out that information from the ROM and it isn't possible to use those tools to format and partition a drive with a different geometry, while the original Xebec tools (that I'm searching for) allowed to enter an arbitrary drive geometry with cylinders and heads according to the manuals I have (a bit like in old PCs were IBM initially only supported a fixed number of geometries until later BIOS versions allowed to enter arbitrary HDD geometries). Actually my plan B is to convert my system into a Sider from a software perspective by exchanging the ROM on my host adapter with an EPROM burned with a Sider ROM image (that I also have to find first) for a drive with equal or smaller geometry values than the BASF drive that I have here and to use the Sider tools to format it afterwards...
 
I might be interested in going the other way; I had the idea to try to use an old 8" Bernoulli drive with the thing. It didn't work and I didn't pursue it very far; I didn't realize drive geometry was in the ROM for the Sider.
 
bear said:
I might be interested in going the other way; I had the idea to try to use an old 8" Bernoulli drive with the thing. It didn't work and I didn't pursue it very far; I didn't realize drive geometry was in the ROM for the Sider.
Click to expand...
Keep in mind that the Sider host adapter predates the SCSI standard. Not guaranteed that a SCSI device will work correctly since all bus phase management is handled in software rather than a dedicated controller chip.
 
Klotho said:
I knew that those Xebec host adapters were also used by the Sider HDDs - but from want I found out, they were apparently using a different ROM on the host adapter for each hard disk type the system was shipped with the drive geometry in that ROM. I found the Sider manuals on the web and from what I saw there, the Sider tools read out that information from the ROM and it isn't possible to use those tools to format and partition a drive with a different geometry, while the original Xebec tools (that I'm searching for) allowed to enter an arbitrary drive geometry with cylinders and heads according to the manuals I have (a bit like in old PCs were IBM initially only supported a fixed number of geometries until later BIOS versions allowed to enter arbitrary HDD geometries). Actually my plan B is to convert my system into a Sider from a software perspective by exchanging the ROM on my host adapter with an EPROM burned with a Sider ROM image (that I also have to find first) for a drive with equal or smaller geometry values than the BASF drive that I have here and to use the Sider tools to format it afterwards...
Click to expand...
No, the drive geometry is hardcoded into the 'custom' S1410A firmware. The HBA ROMs are not geometry specific.
Sider utilities has hidden option for specifying drive geometry. Xebec later bound check the option input to block access, but since it's written in Applesoft...
 
dorkbert said:
No, the drive geometry is hardcoded into the 'custom' S1410A firmware. The HBA ROMs are not geometry specific.
Sider utilities has hidden option for specifying drive geometry. Xebec later bound check the option input to block access, but since it's written in Applesoft...
Click to expand...
Can you elaborate on this a bit for those of us to whom this is new information?
 
This is a combination of information I gathered from Sapphire (LeftWall), Xebec/Firstclass tech support and web.
I was trying to put together HDD for my II+ and we were sourcing the parts from Weirdstuff (when they were still at Sycamore Drive in Milpitas)
Sapphire was running his BBS (this was three decades ago) on a setup he strung together using Datamac HBA and stock S1410 (or S1410A) with a ST225.

He shared with me his collection of Datamac/Siderware that had the hidden option. I glanced over the code decades ago and my take away at the time was that later siderware versions had modified the input bounds check to block access to the hidden option; the actual code that allows user to input custom drive geometry is still in place, just that it isn't called anymore. It's all in Applesoft, so should be fairly easy to undo the block.

I spoke to Xebec/Firstclass tech support in the late 80s about the possibility of using Datamac HBA with S1410A, which I was told that a custom firmware with hardcode drive geometry from a Sider is needed.

Then I found this doc somewhere on the web a few years ago on patching S1410 firmware with hardcoded drive geometry.
 

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