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Best SCSI disks to use on Quadra 900?

valejacobo

Active member
Hi Guys, it's your boy Valito here.

After some fiddling with the boot disks on my Quadra, I've come to the conclusion that my Seagate drive has died efectively; probably can be recovered, you know those old bastards never die, but I'm without a working computer atm.

Unfortunately, due to import taxes in my country, buying a BlueSCSI/SCSI2SD/RaSCSI/whatever solid state drive replacement is not worthy at the moment, due to time and cost, so my best second chance is to find a used SCSI drive on the local marketplace and adapt it.
Now the question in place is: What's the best I should aim for? I know 50 pin SCSI are harder to find by the day, and that the 68 pin are almost directly compatible. Should I aim for one of those with one of those adapter boards? Anyone here has had experience with adapted SCSIs?
 

Cory5412

Daring Pioneer of the Future
Staff member
software and capacity notes:

7.6.1 on a Quadra will be able to format and use volumes up to 2TB and a Quadra 900 is big enough and has cooling to cool hot disks. (if you're running 8.1 you can partition it to a small boot volume and a bigger HFS+ data volume, too.)

7.1-7.5.5's max volume size is 4-gigs, but on a Quadra you should be able to split a bigger disk into 4-gig partitions.

Plain HFS formatting makes "inefficient" use of volumes bigger than about 4GB but it's not worth worrying about. At worst, if you manage to get like a 147 gig disk or so and you really care a lot about efficiently using the space, just do a 4-gig boot disk and fill a secondary data disk with diskcopy 6 images, or just go for OS 8.1 so you can do an HFS+ data partition.

So, anything that's physically compatible should work. You may need a third party disk tool like silverlining, lido, or hd toolkit to partition/format a non-Apple drive.
 

chillin

Well-known member
If I had a 900, I'd want to find a fast wide SCSI NuBus card with internal fast wide scsi (oddly a lot of them only have an external port), then uncover adapter from fast-wide to Ultra, and an Ultra160 to SATA adapter, install the smallest, cheapest SSD I could find, and enjoy close to the theoretical maximum of 20MB/s storage bandwidth. And if I found an UltraWide SCSI NuBus card, I'd use that instead for 40MB/s (probably didn't exist in NuBus).

Then I'd look for Rockets and DOS cards, also Sound Designer II cards.

Filling up 5 NuBus slots is fun to think about. No reason not to find a big old Apple monitor and a card that can drive it in 24-bit color, like, say, a Macintosh 21" Color monitor, which I believe were period appropriate for Quadra 900.
 
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Unknown_K

Well-known member
The most common SCSI drives are SE and LVD that come in 50, 68, and SCA connectors.

Working 50 pin drives are pricey these days since they are in demand and most are in use or recycled by now.

68pin would also work if you can get a 68 pin to 50 pin SCSI adapter.

The last are SCA drives commonly found in old servers that had removable trays. The problem with SCA are they have no built in termination and So even when you attach the adapter and provide power you need to have a 50 pin SCSI cable with termination on the end (assuming your SCA adapter is 50 pin and not just 68 pin where you would need an adaper).

You can also directly use a 68 pin SCSI card like the FWB jackhammer but those are expensive. The only other options for a Q900/950 would be a super rare/expensive PDS SCSI card.
 

Cory5412

Daring Pioneer of the Future
Staff member
Ultra160 to SATA adapter, install the smallest, cheapest SSD I could find


It's my understanding that these adapters are quite expensive. Like, well more than the cost of a more modest NuBus SCSI card, a SCSI2SD V6, and a high end SD card all put together. I'd say to reserve an UltraSCSI to SATA adapter for something a little higher end that has any chance of making decent use of the storage performance, and then go for a bigger or midrange SSD to pair with it. Fortunately, we don't have to deal with that because PCI Macs can just have SATA cards added or we can use cheap IDE <> SATA adapters.

And, to be honest, if you're building a 900 as a high end system and need that much throughput the scsi2sd v6 is probably the best option. As far as I'm aware it's the fastest of the SCSI replacers. I get 7MB/sec out of mine on an 8600/300, I've seen people get a full 10MB/sec out of them on either Jackhammers or SEIVs.

That said: if you're not doing, say, "Technical Computing" (development in particular) or running a DAW or a video editing workstation, the performance of any random contemporary disk or any of the other lower performance SCSI replacers (scsi2sd v5, bluescsi, rascsi, forgot where macsd falls on this but IIRC it's kind of inbetween v5 and v6 at transfer performance) will work fine.

Pretty much any of the SCSI replacers will be an improvement over a stock disk when it comes to random access and seek and those things are most of what can make or break a computer feeling responsive

Though, OP requested options other than those because they're expensive and difficult to get locally. For that reason, USCSI to SATA adapters are probably also disqualified unless OP happens to be directly involved with ewasting a 2000s-era money counter that used them.
 

chillin

Well-known member
SCSI to SATA adapters cost precisely the same as any of the SCSI2SD devices, they're just trickier to find, though probably not as hard to find as the Apple PDS cache+fast wide SCSI card for WGS95. Also, A V6 SCSI2SD tops out at fast SCSI 10MB/s, half the speed of fast wide SCSI. 100% improvement is not negligible. You could do better than a V6 SCSI2SD with the PDS fast wide SCSI card and a fast wide SCSI spinning disk (though they are old and expensive, and you won't see 20MB/s without RAID, just better than 10MB/s).

That said, it is painless to find, purchase, install and use SCSI2SD. I think it is a great product, just wish they were $50-$60 rather than $90-$130.
 

Cory5412

Daring Pioneer of the Future
Staff member
Apologies in advance if this sounds severe. It's not meant to be, but I had to re-edit/rewrite it a few times for brevity and clarity. (Ironically, it came out longer but I feel like it's more readable.)

From a numbers perspective: 100% is not negligible.
From a reality perspective: Classic Macs are bad computers that could barely use the hardware that was given to them when new. Putting a server disk from 2002 in a Mac desktop from 1992 barely makes any sense even in 2008 when both of those things are ewaste.

This, as with any other technology problem, has several available solutions, and they each have good and bad points. Any given choice is a set of compromises. Fast solutions cost a lot. Cheap solutions will likely be slower. The fastest solutions are even more expensive and uncommon.

For most vintage Mac use cases, a SCSI to SATA bridge is massively overpowered, even before you connect it to an upgraded SCSI card. Not all, but most. If I had to guess, 95% of vintage Mac users are within the "normal" band on this one.

When choosing a storage device, most people will get more perceivable benefit out of an SD card SCSI replacer that has fast seeks and accesses. SCSI2SD, MacSD, BlueSCSI, RaSCSI, et al should all do this well.

SCSI2SD v6 has the added benefit of being able to win sequential transfer drag races among that group. I have a SCSI2SD v6 in an 8600/300 running 9.1 and everything's sprightly compared to the stock disk for this type of machine.

The biggest disadvantage of SD-card based disk replacers are going to be if you're within that 5% of people that are doing stuff like video capture or linux/bsd software building that hit the disk really hard or require longer-term sustained write performance, which as far as I can tell is a weakness of even the v6. (I've been wanting to put more VRAM in my 8500 or 8600 and test this out -- one day.)

w/re pricing:
The SCSI2SD v5s are around that 50-60 mark, and for basically anything pre-PCI, day to day on a v5 should be great. v6s are a bit closer to that $90-130 or so mark. Granted, it looks like they're out of stock at the moment.

w/re SCSI to SATA adapters: I don't normally look because these are traditionally both very expensive and uncommon. They were a niche product sold almost exclusively for the purpose of life-extending high end database and transaction processing machines at giant corporations and banks. Workstations and small servers never needed them because those machines were replaced 1:1 with SATA computers in the mid-2000s, so acard's adapters weren't ever produced at any scale even remotely resembling anything from Apple or replicated quite to the scale that, say, sata to ide adapters were.

I found two varieties on ebay right now:
One for $300 says it'll let you use a SATA ODD: https://www.ebay.com/itm/255195139923/
The other for $2000 lets you put a 2.5 SATA HDD/SSD into a 3.5 SCA bay: https://www.ebay.com/itm/263823727507

If there's a big stockpile of these hanging around somewhere more affordably I would love ot know, but if I had to guess, that's a pipe dream for most of us.

So, I think it's worth talking about in the context of that 5% of people or machines that have needs met poorly by SD cards, and helping people evaluate where their needs probably are. Even ~midrange video capture doesn't usually need, say, over 10MB/sec -- In 1995 or 1996 MacWorld was suggesting a disk that could get 5MB/sec sustained writes for capturing video from the built-in video on a PowerMac 7500 or 8500. MacWorld floated the idea of using a Radius System 100 with a disk setup that could do almost 3MB/sec. (Huge PDF: PDF page 111, MacWorld February 1996)

So, honestly, getting high end storage for most Mac people isn't all that important for practical use cases. Getting over 10MB/sec on any Mac from before like 1997 is mostly good for showing off or saying you did it.
 

Cory5412

Daring Pioneer of the Future
Staff member
jt located this one: https://www.ebay.com/itm/153754011613 - but I think this is the device that really only claims to work with optical devices.

the 7730 I linked above for $300 seems to be more generic, but $300 can get you three SCSI2SD v6es or five SCSI2SD v5s, so it's sort of a question of what your priorities are and what kind of system you have. For my part, five SCSI2SD v5s will go further in the hobby than a single uscsi <> SATA bridge.

If more like $30 is what these are actually going for and they work with hard disks, that's more compelling for sure, but that's a lot of ifs and while that makes this a worth-documenting option, it's by no means necessary to go all the way there in all situations.
 

chillin

Well-known member
I think you're maybe mischaracterizing my statements. A $15 SSD at the end of a chain of adapters is not high end storage. And I think you may have some bad eBay examples.
This is about the price of a thing, and I know it because it sold:

Cost is relative. Not sure why anyone would, but one could spend a lot maxing out each SCSI bus with all the SCSI2SD that it will take, and that would not be cheap considering each bus takes 6 extra SCSI devices, and there is more than one bus, but this won't increase the bandwidth of the SCSI-1 or fast SCSI-2 bus.

Faster storage bandwidth, same as any bus or proc speed increase, translates directly to more work getting done in less time. Perhaps you are satisfied with fast scsi speeds, and perhaps most are, and I think that's super. I was merely trying to answer the question, "what is the best," which I read as "what is possible or available" or "what can be done?" And because it is a Q900, the first thing I thought of was Apple's PDS Cache/fast wide SCSI card. So what can be done, with a Q900 is 20MB/s. And it won't work in anything but a Quadra 900/950 (WGS95). What can be done is achieving the fastest storage bandwidth of any 68k Mac. And I provided a quick and over-simplified route to theoretical maximum bandwidth. And I'm not arguing "should," I am saying "could," and even "I wish I had."

Are you saying we can't, or shouldn't, or it is not reasonable, due to cost or availability? I accept this. But given the chance, I'd do it anyway, and maybe not tell you about it to avoid distrubing your serenity,
 
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Unknown_K

Well-known member
So, I think it's worth talking about in the context of that 5% of people or machines that have needs met poorly by SD cards, and helping people evaluate where their needs probably are. Even ~midrange video capture doesn't usually need, say, over 10MB/sec -- In 1995 or 1996 MacWorld was suggesting a disk that could get 5MB/sec sustained writes for capturing video from the built-in video on a PowerMac 7500 or 8500. MacWorld floated the idea of using a Radius System 100 with a disk setup that could do almost 3MB/sec. (Huge PDF: PDF page 111, MacWorld February 1996)

So, honestly, getting high end storage for most Mac people isn't all that important for practical use cases. Getting over 10MB/sec on any Mac from before like 1997 is mostly good for showing off or saying you did it.
Back in the 90's most disks had a much higher read then writing speed plus drives had thermal calibration being done that caused dips. If you were video capture that was a deal breaker.

Even today most users care about read speeds to speed up program and OS boot times and not so much write speeds.

Something to think about if you have more than a couple machines and want a cheap storage/OS solution is to just use external drives. Something like a Medea Videoraid can sometimes be found for $50 if you are patient and has a 68 pin connection that can be adapted cheaply (video external SCSI cables) down to a Mac SE if needed. You can have multiple partitions with different OS for each machine and it will saturate any SCSI bus you can connect to it. You can also get a SCSI to Firewire adapter (if you wait for a deal) and use a cheap external firewire drive.
 

Cory5412

Daring Pioneer of the Future
Staff member
Are you saying we can't, or shouldn't, or it is not reasonable, due to cost or availability? I accept this. But given the chance, I'd do it anyway, and maybe not tell you about it to avoid distrubing your serenity,


My apologies for the confusion.

This thread isn't about you, and it's not about a hypothetical.

The original post outlines a very specific situation:
  • SCSI disk to boot a Quadra 900
  • Buying and importing a modern SCSI disk replacer, of any kind, costs too much.

SCSI2SD v5 is about $65 and BlueSCSI is about $60 to we can presume that we're working with a budget of a bit under a hundred total US dollars.

So in this case, "best" has some qualifications added to it.

I appreciate that it's possible to know the best possible combination of peripherals for a particular Mac, and think that if you want to build it -- you should, I'll be happy that you're happy.

Your proposed option, in this case, however, costs too much.

The USCSI or UWSCSI path makes sense, you can often find ex-server disks really cheap, so the appropriate 50 to SCA/68/80-pin adapter and an ex-server hard disk would probably be a great option. It'll let whatever's already in the 950 stretch it's legs and if OP wants to buy the PDS card later it'll probably still max out that card's throughput.
 

Cory5412

Daring Pioneer of the Future
Staff member
Separating this out as it's kind of tangential.

Very few people who are using vintage Macs are doing professional work on them, so for most people, the actual performance of their vintage computers literally doesn't matter.

My consistent suggestion to people who are using or who are thinking about using vintage Macs for some kind of professional work is: Please consider not doing that.

Vintage Macs are not fast and they don't do anything fast. They weren't even fast when they were new. These are aging machines that will require more and more maintenance as time goes on, and the maintenance they need will require replacing successively more/larger parts of the machine, creating new workflows to accomplish tasks that were simple in 1992, or require more and more skills to repair existing parts.

As a professional and/or in your professional work: What's your time worth? Is it worth enough that waiting for a 68k Mac or spending your professional time doing maintenance on 30 year old computer hardware is a good use of that time?''

From a vintage computing hobby perspective, most people that I've seen don't profess to value their time working on the machine in the same way they would place value on their time working on a new computer achieving results or finishing more jobs in less time.

That's of course a personal decision, but for me, using a vintage computer is at least as much about marinating in the vibes of a past I didn't quite have and the optimism for an alternate future as it is about getting any specific thing done.

Faster storage bandwidth, same as any bus or proc speed increase, translates directly to more work getting done in less time.

Unfortunately this is literally not true with most use cases on Classic Mac OS. It's pretty much like DOS 6 and Windows 3 which are roughly the same speed on a 486/66 with 8 megs of ram booting off a dying hard disk and a 3GHz Core i7 with a top spec 6-gigabit SATA SSD.

In my experience, for each version of the Classic Mac OS, you can upgrade up to a certain point at which system and OS tasks and daily productivity, edutainment, communication, and utility software will be as fast as it ever will be and then you pretty much won't get any more performance out of that system. You can only launch ClarisWorks 4 so fast. A spell check can only happen so instantaneously.

To that point, I mentioned I have a SCSI2SD v6 connected to an 8600/300 running Mac OS 9.1. I get maybe 7MB/sec read and 6.5MB/sec write in optimal circumstances and everything feels perfectly fine on that machine. That's a computer that's roughly a couple hundred times faster than a Quadra 900. (Accounting for both IPC and clock speed differences.) I strongly suspect I could put the SCSI2SD v6 in my Beige G3/300 and, well, it would feel faster, but I don't really know how much.

The main exception to this is "high end" usage that introduces significant wait periods -- rendering, compiling, running a compute task like a statistical analysis, file compression/decompression, etc etc. In most vintage Mac contexts, the CPU and the OS itself are the limiting factors -- not the storage.

In a Quadra 900, the 25MHz 68040 is going to run out of steam way before a 5-10MB/sec disk does.

The one benefit you really get out of adding newer storage to older Macs is by switching them to solid state storage such as SSDs or SD/CF cards, where you get better random r/w performance and lower seek and access times. You can probably get just about as much benefit out of that as you'll ever get from a SCSI2SD.

On G3/4/5-era machines, you can feel individual upgrades when you're runnign Mac OS X. Mac OS X has a much better architected overall base that makes much better use of the system's hardware in lots of ways.

(This starts to get into a bit of a rabbit-hole scenario where if your goal is "performance" or "reliability" or "achieving work" you can justify a slightly newer computer all the way up to literally an M1 Max MacBook Pro or a 2019 Mac Pro, so there's always a point at which you have to say "I'm stopping here because this is the experience I want.")
 

Cory5412

Daring Pioneer of the Future
Staff member
Even today most users care about read speeds to speed up program and OS boot times and not so much write speeds.

The measure that actually impacts perceived speed, especially on modern OSes like Mac OS X/macOS and Windows Vista and newer is IOPS, which is sort of a different way to measure seek and access speed. Essentially, the modern computing experience typically involves a few dozen processes reading and writing data from random areas of any number of disks at once, so IOPS matters more to the way a computer "feels" than the raw drag-race sequential read or write speed.

To complete the car comparison: A mini cooper or a mazda miata can turn faster on tighter corners than an drag race car can.

You can also get a SCSI to Firewire adapter (if you wait for a deal) and use a cheap external firewire drive.

Do you have a part number on that? I'm only aware of the reverse: adapters to use SCSI devices like Zip/Jaz/Orb/SyJet or scanners on USB/Firewire computers.
 

Cory5412

Daring Pioneer of the Future
Staff member
My apologies for getting us sidetracked.

To call back to the original post: Apple used 50-pin SCSI disks until around 1998 and it looks like you can find 50-pin SCSI disks up to around 4-9 gigs or so, there's probably a handful up to 18 gigs.

Genuinely, if your limitation here is that importing a SCSI2SD or BlueSCSI is too expensive, my recommendation is that you hop on your local auction site and see what you can get in 50-pin or SCA/68-pin SCSI disks less than whatever that amount of money is. (I didn't spend any time researching that so you'll have to fill in that detail.)

There's a variety of 50-pin 1-9 gig SCSI disks on US eBay for well under a hundo, There's a couple for under $25 shipped. I would aim for 1 gig or bigger since in general that'll represent high-performance disks from 1990-1994 or Good Enough disks from ~1995+, so it'll be akin to buying a reasonable midrange upgrade for your machine in 1995 or 1996.

Just for comparison, this is in the US but here's a claimed working pull for $22 shipped: https://www.ebay.com/itm/333516850133

Just by way of comparison, in the US:
- BlueSCSI is around $60
- SCSI2SD v5 is around $65
- SCSI2SD v6 is around $100

Add the cost of whatever size and quality SD card you want to either of those (you have to use a good SD card to get the most out of the v6, for example, so thatll be $20-30, depending) and you've spent more money than if you just bought another vintage disk, but you've saved yourself a lot of time, and the SCSI2SD v6 in particular is faster than most contemporary '90s disks. (The Seagate Elite 47 from 1998 claims a peak sequential transfer rate of a blistering 23 MB/sec, and that was a high end video/capacity oriented disk.) (Don't go for a Seagate Elite, at least the 47 -- they're regularly listed on eBay for several hundred dollars as collector's items.)
 

chillin

Well-known member
In a Quadra 900, the 25MHz 68040 is going to run out of steam way before a 5-10MB/sec disk does.

I appreciate your opinion and that you feel strongly about the economics of vintage computers. However, the bottleneck on any 68040 mac is going to be the fast SCSI-2 bus. I do not know the precise memory bandwidth of a 25MHz 68040, but I recall that in a 16MHz 68030 SE/30, the memory bandwidth is 15MB/s, and I have seen it estimated a 68040 is 3x faster than a 68030 at the same clock speed (actually, the estimation is "3-5 times faster"). The IIfx memory bandwidth is much greater than in an SE/30, and the Q900 was advertised to be twice as fast as a 40Mhz 68030 IIfx. A single fast SCSI-2 device, by itself, can not exhaust a 16MHz 68030, nor a 40MHz 68030, let alone a 25MHz 68040.

If there's a SCSI-1 or fast SCSI-2 bus in your 32-bit or 16-bit machine, whether aware of it or not, what you mostly are waiting for is that bus. Double the storage bus speed, double the performance, and it won't be incremental, but a substantial performance gain across the board.

While the reality is fast SCSI-2 10MB/s was still more or less state-of-the-art in late 1991 when Q900 was first released, the Apple hardware teams had some foresight that SCSI would continue to develop and speeds would increase, thus they included a PDS and NuBus interfaces for expansion to account for future faster storage interfaces, among other things.
 

ArmorAlley

Well-known member
@valejacobo SCSi2SDs can be gotten in Canada at https://decromancer.ooo/scsi2sd/. Remember that prices are in CAD. I have just put in an order. I am awaiting the customs bill from the Swiss government.

Secondly, a 9GB or 18GB LVD/SE drive will fit very nicely into your Q900. I'm fitting out a faster WGS 9150 at the moment and there is space above for cooling. Create 5x or 9x 2GB drives. You can run Mac OS 8.1 on the Q900 so you have the possibility of accessing HFS+ volumes there.

These machines have massive fans but, be warned, these PSUs are starting to fail. Have a look at BadGoldEagle's thread on the QuadrATX for an example (and what can be done). Adapter boards can be gotten on eBay and AliExpress. Be sure to check that they can be terminated.

I also posted a thread some weeks' back on RAID, which might interest you, if you can find two drives of the same spec, and would greatly improve if you could find an FWB JackHammer or ATTO SiliconExpress IV and implement RAID 1 (mirroring). You could see if there is a performance improevement with RAID 0 (striping) but since these drives are anyway old, and they have to be shipped to you, I'm not sure how long they have to live.

Unless you can get some 9GB or 18GB SCSI drives cheaply (including postage), I think that the SCSI2SD etc. is your best bet.
 

joshc

Well-known member
Secondly, a 9GB or 18GB LVD/SE drive will fit very nicely into your Q900.
+1 to this, I've used similar 68 pin drives in Macs using @max1zzz's adapter, but other 68 pin -> 50 pin SCSI adapters are available, that's what I'd go with if you're not looking for an SD card based solution.

SCSI -> SATA seems like an unnecessary step when SCSI adapters are available.

Most any storage will do just fine in a Q900, be it a slower option like a BlueSCSI, a spinning disk either 50 pin or 68pin or a SCSI2SD.
 

cheesestraws

Well-known member
The correct answer here, honestly, is "whatever you can get and afford and is compatible". 68 pin + an adapter might be the most sensible option if you can get those. I use that in one of my machines, like @joshc, with one of @max1zzz's adapters. If you can get those locally it ought to work fine, modulo any termination weirdness.

Disregard people who want you to do complicated things. It is very rarely, pragmatically speaking, worth it. SCSI to SATA is a very expensive way to have exactly the same experience as you would with cheaper options. IDE to SCSI is expensive too unless you're trag and have an attic full of the things. Getting a new SCSI card is also, for most people, a total waste of time (and I say this as someone who has the weird unobtanium 040 PDS SCSI card in my 950—it is a fascinating bit of hardware, but it doesn't much change how I use the machine). The WGS card is also irrelevant, as it won't work under MacOS. Chasing this kind of thing is a good way to turn an already-complicated problem into a totally entangling one.

Find something that works and use it—then upgrade it later, if you need to or want to.
 

MacKilRoy

Well-known member
For the best 'vintage' experience, and for the lowest possible cost, I have purchased a few SCSI LVD SCA80 pin drives, together with the proper adapter like max1zzz's adapter (or others). Drives can often be sourced for around $20, and the adapter is about that, so let's just say around $50 complete. Yes, it's in SCSI2SD territory, but it is less expensive, and if you have the right adapter, you can source a few drives to replace. I have many old Apple Quantum and Connor drives that are completely dead, yet I have not had any LVD drives that I purchased used arrive dead (yet).
 
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