ADTX SCSI IDE 2.5 inch Adapter Compatibility and Performance

[David Cook]

Circa 1996, a Japanese company called ADTX produced a SCSI to IDE adapter for 2.5 inch IDE hard drives to work in SCSI Macintosh PowerBook computers. Recently, I purchased one on eBay and got another inside a parts machine PowerBook 165c. Both adapters are labeled part number A360025. I assume the other number (9647 and 9651) on the label is the serial number.



Both ROMs are labeled 10TA32 96/9/07



Curiously, the adapter found in the PowerBook 165c (1993) had an Apple branded IBM 1GB hard drive from 1996 with an ADTX sticker labeled AX-HDD-1298. The date suggests the drive was removed by the user from another machine to install in the PowerBook 165c. Or, the fact that this drive has both an Apple label and ADTX label suggests that maybe ADTX was buying Apple drives and reselling the combination as a replacement for failing drives in older PowerBooks?



There is a cool bridge connector that stacks the drive to the ADTX board. If you buy an ADTX board second-hand, make sure you get this bridge connector with it.



Speaking of which, below is my connector stack to adapt a full-size desktop SCSI machine to a compact flash. Left to right: aberco (eBay) "2.5" to 3.5" SCSI 50 pin laptop hard disk drive adapter Apple PowerBook", ADTX SCSI IDE adapter, ADTX connector, SinLoon "CF to IDE Adapter CF Memory Card to 2.5-inch 44Pin Male IDE Laptop SSD HDD Adapter Card (CF/IDE M)" https://amzn.to/495vLiU, SanDisk Ultra CompactFlash 2GB 15MB/s.



And here is my connector stack to adapt a full-size desktop SCSI machine to an mSata. Same as above except the two items on the far right: Chenyang "mSATA Mini PCI-E SATA SSD to 2.5 inch IDE 44pin Hard Disk Case Enclosure Box White for Notebook Laptop" https://amzn.to/47kHgS7, and DogFish "SSD SATA mSATA 128GB Dogfish Internal Solid State Drive High Performance Hard Drive for Desktop Laptop SATAIII 6Gb/s 128GB" https://amzn.to/46FC4bb



I tried some other CompactFlash adapters and other mSata adapters but they did not work. The ADTX is very fussy.

Additionally, I tried numerous other CompactFlash media without success. All the cards below work in a PC (the IBM microDrive may be dead), and those marked 'IDE' also worked in a Macintosh with a Sonnet Macintosh PCI IDE card.



To be clear. I could not get any of these CompactFlash cards working with the ADTX adapter.

Performance Testing

I expected that mSata media connected to a 68K SCSI Mac through that ADTX adapter would perform significantly better than a miniSD card through a SCSI emulator. I was wrong.

My test setup is a Macintosh IIci without a cache card or NuBus cards (so built-in video), 20MB ram, 128KB disk cache, and System 7.1.

Below is the performance of an external SCSI hard drive (branded APS) IBM 2GB. Notice peak throughput of 1700 KB/s but with a relatively slower Butteryfly and Outer to Inner seek time because the hard drive head has to physically move to reach a track. This means the drive can really pump out data when in the correct position, but there is a little delay (seek time) to find the right track. Performance would suffer on a fragmented volume, random access, or copying a bunch of little files.


Now here is MacSD (stock, not overclocked). This is miniSD media with emulated SCSI hardware. The peak throughput is slower than a physcial hard drive, but the seek times are multiple times faster because there aren't drive heads to move.


Let's check out the IDE IBM hard drive connected to the ADTX, just as I received it from the PowerBook 165c. Note the scale (Y-axis) is half the other charts. This setup performs worse is all regards compared to the MacSD.


But what if we switch to mSata media? Awful throughput.


A clue to the poor performance is in the red text on the above image. I tried other SCSI drivers and it doubled the throughput performance. (The Y-Axis scale is now back to 2048). Something about FWB Hard Disk Toolkit (version 2.0.6) did not jive with the ADTX. However, other than write throughput, MacSD is still better than ADTX mSata.


ADTX with 2GB SanDisk Compact Flash is about the same, except it has glitchy write performance. I tried this test multiple times and got identical results. It's something to do with the Compact Flash erase/write cycles I assume.


The point of all of this is that seeking out a relatively rare ADTX adapter and finding compatible solid-state media and adapters does not produce a performance boost over modern SCSI emulators. Bummer.

Maybe Not Intended?

There are eight dip switches on the ADTX adapter. Perhaps I did not have them set correctly for maximum performance? My initial reverse engineering shows that the dip switches connect to ground on one side and are pulled up through 10K resistors on the other side. All the switches connect to the LSI KL5C80A16CF microcontroller. Okay, so these are software settings.

The leftmost three switches (1, 2, 3) also connect to the external SCSI ID output pins. The only other connected external pin outputs to an external SCSI activity LED.



There are other versions of the ADTX adapter board. Apparently switches 4 & 5 affect termination on those boards. However, on my version, termination is fixed with 1K resistors. That's weird. The termination resistors should be stronger. I suspect this board was intentionally designed for slower performance in exchange for lower power usage, which would be important on a laptop computer.

On my board, switches 4 & 5 change the expressed number of blocks on the media, at least as far as Hard Disk Toolkit sees them:
4 OFF 4 ON
5 OFF 1055376 1583568
5 ON 2116800 16514064

Playing with these switches and the unknown switches (6, 7, 8) did not seem to affect compatability or performance.

So, in summary, just buy a modern SCSI emulator instead.

- David

 

[NJRoadfan]

That Apple branded drive was OEM. They were offered at the tail end of the SCSI PowerBook era because larger 2.5" SCSI drives were not being produced.

 

[alexGS]

This is an extremely useful post for me - thank you - very timely too. I found it by a Google search for “scsi 10ta32”.

One of these IBM 1GB Apple-branded drives with the same adapter arrived in my Powerbook 540c (with smashed LCD).

I was trying to use it with a cheap CF-IDE adapter that looks the same as yours, but I get a single red flash from that, followed by a repeating pattern of six green flashes from the SCSI adapter’s LED. Did you find similar behaviour with all those CF cards that you tried? I have only tried the one, something 1GB from Taiwan that I’ve formatted as a Mac HFS volume in my G3 Powerbook (PC card adapter).

FWB Toolkit on the 540c with 520c display didn’t see anything on the SCSI bus.

I was expecting that a CF card would have somewhat higher throughput than 1MB/second, but at least the seek times look favourable. I don’t have any ‘modern SCSI emulator’ to use, but I have rebuilt a battery for my 540c, and so I was looking forward to low power consumption.

Turning the 540c on was quite funny, though. I didn’t think it was turning on, but then realised the black screen is normal while it checks the 36MB RAM, and of course with no hard drive sound, it was not obvious that it was ‘on’

Maybe I can use the adapter with a newer hard drive, say a Toshiba 4GB that I have. Surely capable of more than 1MB/second? The PDF mentions 5 or 10, but it also mentions IBM drives.

Is there a modern SCSI emulator that uses something other than an SD card? It seems strange to use a serial device when parallel could be much faster. I’ve never understood how SATA drives have been the success they have been

 

[David Cook]

by a repeating pattern of six green flashes from the SCSI adapter’s LED.

Yes, that's exactly what I saw on the non-working media.

Surely capable of more than 1MB/second? The PDF mentions 5 or 10, but it also mentions IBM drives.

The PDF also mentions an active terminator, which my version (and your version?) of the board does not have. Terminators both suppress reflected signals (noise) as well as provide the 'high' signal voltage. The weak terminators on my version of the board use less power (good for laptop) but that means it takes longer to pull up to the 'high' signal voltage on each line as it changes digital state. It is my theory that they intentionally slowed down the speed of this version of the board to compensate for rise time of the weak terminator.

I don't believe the media (IBM hard drive, compact flash, mSata, etc) is causing a bottleneck. Looking at my charts, the hard drive (955 KB/s), the mSata (1102 KB/s), and the compact flash (1082 KB/s) are within 15% of each other. That suggests the board is holding them back.

I share your disappointment that the ADTX is not demonstrating superior performance over an SD card solution.

 

[alexGS]

Thank you for your work in testing/benchmarking. I think you’ve saved me a lot of time and puzzlement.

The 1GB drive I have seems to have significant rotational noise (similar to the earlier drives), I will try to replace with another small IDE laptop drive of the period. I agree with your point about the active termination, I also wonder whether the SCSI in the Powerbook 500-series is always slow.

I will look for an SD-based solution as well. Not for performance, but just to eliminate noise and reduce power consumption, so that I can play with my Powerbook on the couch while my partner watches TV. This might never happen anyway, as I’m not sure what ‘killer apps’ I’ll be running

 

[alexGS]

For the record, today I’ve also tried using two IDE 2.5” slim (12.7mm) drives from the late 90s: a Toshiba 4GB and an IBM 6GB. Both are detected by the adapter and by Apple SC Setup. Both will format and verify (a process that takes about four hours). Neither will mount at the end of that process, which is frustrating. Though not as frustrating as using FWB toolkit, which won’t fit on a startup disk with the Powerbook 520/540 enabler, and thus requires about fifty disk swaps with the Disk Tools disk to start. And then does the same thing; formats in a few hours but cannot mount the drives.

Perhaps it is a size problem. I presume (from my experience on other Macs) if Apple SC setup required an Apple drive to work, it wouldn’t show the other drives at all or attempt to format them. Of course, the adapter and Apple SC setup have no problem formatting and mounting the 1GB drive the adapter came with. It’s just a bit noisy (rotational noises).

So in summary, this adapter provides hours of fun for trying to get other hard drives working - as well as for CF cards

 

[David Cook]

this adapter provides hours of fun for trying to get other hard drives working

If it helps, I had success using Anubis 2.5.4 (https://www.macintoshrepository.org/software_search.php?s=anubis&sid=&p=1) and SCSI Director Pro 4 (https://www.macintoshrepository.org/33004-scsi-director-pro-4-0). The latter is also what I used to generate the performance graphs.

 

[alexGS]

If it helps, I had success using Anubis 2.5.4 (https://www.macintoshrepository.org/software_search.php?s=anubis&sid=&p=1) and SCSI Director Pro 4 (https://www.macintoshrepository.org/33004-scsi-director-pro-4-0). The latter is also what I used to generate the performance graphs.

Thank you, I will get both of those.

Apple SC Setup and FWB toolkit both recognised and formatted the drives but I think the problems with mounting are because both drives are over 4GB. Does that mean they have to be HFS+? That would mean System 7.5 or later - I guess the original Disk Tools and setup disk set (7.1.1) for the 520/540 can’t be used, and the version of FWB toolkit that I’ve got is probably too old as well. Rookie mistake!

 

[eharmon]

I wonder if the adapter only works with certain drive types (heads, cylinders, etc)? Things of that era could have weird compatibility issues in certain instances -- I have a Pentium BIOS that requires a really specific configuration for > 2GiB drives or it crashes (and won't let me use the full size of the drive). But after some fiddling you can get it to work with CF cards.

I wonder if those other DIP switches affect that, but you still weren't able to find something compatible with the way the other CF cards are being exposed?

 

[alexGS]

I am really happy to report that a Sandisk Extreme III 2GB card (and IDE connector board) works with the ATDX adapter Apple SC Setup is happy to format it.

My earlier problems with drives 4GB and 6GB not mounting (after formatting) were caused by using the System 7.1.1 Disk Tools disk; I got both those drives working with the System 7.5.3 Disk Tools.

I bought the CF card not expecting much; considering that all other cards I had tried had not worked. It cost the equivalent of about US$12 second-hand.

I’m already enjoying my noiseless Powerbook 540c (just waiting for the replacement LCD now; it’s using a 520c display in the meantime), and can’t wait to see how long the battery runs for in typical use.

Yes, I know the CF card has a limited number of read/write cycles but I don’t think that will really be a problem here time will tell…

 

[David Cook]

I am really happy to report that a Sandisk Extreme III 2GB card (and IDE connector board) works with the ATDX adapter Apple SC Setup is happy to format it.

My earlier problems with drives 4GB and 6GB not mounting (after formatting) were caused by using the System 7.1.1 Disk Tools disk; I got both those drives working with the System 7.5.3 Disk Tools.

I bought the CF card not expecting much; considering that all other cards I had tried had not worked. It cost the equivalent of about US$12 second-hand.

I’m already enjoying my noiseless Powerbook 540c (just waiting for the replacement LCD now; it’s using a 520c display in the meantime), and can’t wait to see how long the battery runs for in typical use.

Yes, I know the CF card has a limited number of read/write cycles but I don’t think that will really be a problem here time will tell…

Congratulations! Glad to hear the update.

 

[hauke]

For the record, today I’ve also tried using two IDE 2.5” slim (12.7mm) drives from the late 90s: a Toshiba 4GB and an IBM 6GB. Both are detected by the adapter and by Apple SC Setup. Both will format and verify (a process that takes about four hours). Neither will mount at the end of that process, which is frustrating.

Note that the internal SCSI Powerbook drives have to be terminated to work.

I learned this the hard way in the nineties, having picked up a 500 MB drive for my Duo 280, and then having to source and solder on 603 size (IIRC) SMD resistors - I still had the eyesight then.