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Announcing ZuluSCSI - A file-based SCSI device emulator

rabbitholecomputing

Vendor The First
@rabbitholecomputing Quick question, is the AzulSCSI slower than the SCSI2SDv6? Just looking for a little more clarification between scsi2sd vs AzulSCSI. I assume I cannot switch sd cards between the two?
Good question. This is not the answer you're probably hoping for, but as one might expect, "it depends". In some areas, it's slower, and in others, it's faster, particularly when it comes to read performance.

When it comes to read performance, on nearly all 68K and PowerPC Macs, AzulSCSI can be, overall, faster than SCSI2SD V6, and at a much more palatable price point than that of V6. There are also further improvements to AzulSCSI V1.1 write speeds in the pipeline, which will be incorporated in to a future firmware release.

In real-world usage on classic Macs, AzulSCSI is, in our view, an overall better choice than SCSI2SD V6.
 

AndyO

Well-known member
Let's go ahead and wrap this up w/re the name. I think we've gotten as much out of this as we really can.

The point has been sufficiently made: If you were designing, building, and selling this device, you would have given it a different name.

The issue isn't with the fact some would have given it a different name. That's rather like suggesting that if this were a trademark infringement case, the problem would lie with those complaining about the alleged infringement, not the people responsible for it.

That said, my personal view is that firstly, just about any and every product which can be used to solve a problem with the ownership, maintenance or use of our old computers is a good thing, to be welcomed. And secondly, that the backstory and personalization in this thread and others relating to SCSI-replacement devices really needs to stop. It's pointless, destructive, and helps absolutely nobody.

In a thread of mine last year, I asked for advice on making what ought to have been a simple choice, and the same nonsense sprang up there too. The only way I actually got help was when a member here PMed me to provide some guidance, because it was pointless to try in the thread.
 

macuserman

Well-known member
In real-world usage on classic Macs, AzulSCSI is, in our view, an overall better choice than SCSI2SD V6.
And when you say "classic macs" does that include both 68K and PowerPC? PowerPC with G3/G4 upgrades? Just trying to understand if there is any real performance hit in these vs the scsi2sd or if I should just embrace them whole heartedly for my purposes. :) My primary use is on PowerPC often with G3/G4 accelerators installed.

I'd like to be able to switch images by swapping sd cards easily between various machines, but I was only able to secure one v6 module before supply chain issues hit and haven't had much luck waiting for that to get fixed so just wondering if jumping on the Azul wagon fully will do everything I want or if later I might want to get some of the scsi2sd when/if they became available again.
 

Daniël

Well-known member
PowerPC with G3/G4 upgrades? Just trying to understand if there is any real performance hit in these vs the scsi2sd or if I should just embrace them whole heartedly for my purposes. :) My primary use is on PowerPC often with G3/G4 accelerators installed.

I think that PCI Macs (which are the ones most suitable for G3/G4 accelerators) are better to use with things like SIL3112 SATA cards. While it can be more pricey if you can't replace and flash the EEPROM yourself (premodded cards are about $50 on eBay, but still require a separate SSD or HDD), and they still hold modern SSDs back quite a bit, they'll still be much faster than SCSI SD replacement drives. I think it's NuBus and earlier where SCSI SD replacements fit the best.
 

Skate323k137

Well-known member
Let's go ahead and wrap this up w/re the name. I think we've gotten as much out of this as we really can.

The point has been sufficiently made: If you were designing, building, and selling this device, you would have given it a different name.
It's not about what I would name it, that is quite frankly irrelevant. My point is that it's well established that the name confuses the source of the product, and subsequently I don't voluntarily do business with people who choose to act like this when asked about it. And with that I'll see myself out of this thread, I hope.
 

macuserman

Well-known member
I think that PCI Macs (which are the ones most suitable for G3/G4 accelerators) are better to use with things like SIL3112 SATA cards. While it can be more pricey if you can't replace and flash the EEPROM yourself (premodded cards are about $50 on eBay, but still require a separate SSD or HDD), and they still hold modern SSDs back quite a bit, they'll still be much faster than SCSI SD replacement drives. I think it's NuBus and earlier where SCSI SD replacements fit the best.
I've had good success with modding and creating the pci sata cards I have a bunch of cards and chips etc for that whenever I need to make one, but I still just prefer not to have to use a PCI card for the hardrive situation if possible, I don't know why I just don't like it as much. I generally prefer to use the pci sata cards in G3/G4 machines that came that way and have IDE drives by default. In the beige machines I really like scsi just for myself.
 

sirpete

New member
What about systems like the Amiga 2000 / 3000 / 4000? Will AzulSCSI performance be better or worse than SCSI2SD V6?
 

Juror22

Well-known member
Both SCSI2SD and AzulSCSI can emulate CD-ROM drives with 512 byte sectors. The default with AzulSCSI is 2048, but you can override it by naming a file "CDn_512.iso"
Very happy to hear that some advanced thinking went into the configurations, with thoughts toward extensibility beyond just the basic settings. It definitely broadens the appeal for me - that's why I have my first one on the way. :)
 

joshc

Well-known member
I'm glad to report I've got an AzulSCSI working well in my SE. I haven't done any benchmarks yet but my main observation so far, when comparing it to BlueSCSI, is that AzulSCSI is far better thought out in terms of configuration/debugging options.

DIP switches on the board itself make this easy as described in the README on GitHub.

The other big bonus is the active development of the firmware, so I'm keen to see what other features come soon as well.
 

MrFahrenheit

Well-known member
Is the firmware easier to flash onto AzulSCSI vs older BlueSCSI (most recent BlueSCSI allows USB flashing but prior it required an EPROM flash, if I recall correctly)?
 

rabbitholecomputing

Vendor The First
Is the firmware easier to flash onto AzulSCSI vs older BlueSCSI (most recent BlueSCSI allows USB flashing but prior it required an EPROM flash, if I recall correctly)?
Yes! we implemented a custom bootloader which simply looks for a file on the SD card, at power up. If it's there, it self-updates the firmware, which takes about 1.5 seconds. It then removes this firmware update file (so it doesn't go in to an infinite loop), and resets itself.

The silicon still supports DFU in ROM, and that's still the back-up/rescue/failsafe mechanism for flashing firmware via USB, were something to go wrong during an update.
 

Fizzbinn

Well-known member
The other big bonus is the active development of the firmware, so I'm keen to see what other features come soon as well.
Bonus compared to? I know I’ve updated the firmware on my SCSI2SD units in the past and there are updates for BlueSCSI as well.

Yes! we implemented a custom bootloader which simply looks for a file on the SD card, at power up. If it's there, it self-updates the firmware, which takes about 1.5 seconds. It then removes this firmware update file (so it doesn't go in to an infinite loop), and resets itself.

The silicon still supports DFU in ROM, and that's still the back-up/rescue/failsafe mechanism for flashing firmware via USB, were something to go wrong during an update.

Neat!
 

Alumamac

Active member
Is the optional external db25 supposed to be female? The one they put on mine is male, though.
I’m not sure, but it would make sense that it would be male since the scsi connector on Macs are female. I suppose if you wanted to use it with a cable that would be problematic.
 

rabbitholecomputing

Vendor The First
Is the optional external db25 supposed to be female? The one they put on mine is male, though.
Correct, the standard connector for external SCSI connections is male. Only the direct-attach SCSI2SD-V5.5-style devices have a male pinout, as they're designed to be directly attached to a DB25 SCSI host port, which is always female on Macs, as well as nearly all other scenarios.

Essentially any 25-pin DB25M-DB25M cable will work. You can usually get them from/fulfilled by Amazon.
 

Powerbase

Well-known member
Correct, the standard connector for external SCSI connections is male. Only the direct-attach SCSI2SD-V5.5-style devices have a male pinout, as they're designed to be directly attached to a DB25 SCSI host port, which is always female on Macs, as well as nearly all other scenarios.

Essentially any 25-pin DB25M-DB25M cable will work. You can usually get them from/fulfilled by Amazon.
Yeah, I figured. My azulscsi had a male db25 soldered to it, unfortunately.

Ill just have to get a switched gender coupler for it. I might just take the scsi cable from my 8500 till I can fix it. I just need them both hooked up to copy everything over to the partitions on the sd card.
 

rabbitholecomputing

Vendor The First
Wow, that shouldn't have happened. We'll get it replaced for you if you want, or send you a DB25F to DB25F adapter, your choice. Please reply to your order confirmation e-mail and we'll get things sorted for you.
 
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