I guess that depends on whether it's on plain old IDE or something like ATA100/133?

Any flash memory on IDE is faster than an SCSI drive, since you have no seek time. Also, SCSI wasn't that much about raw transfer speed, but about little to no CPU usage, which is what actually made an SCSI-based system faster. But of course, you can't compare an old CF/SD card running in PIO 0 mode with some Ultra2Wide SCSI drive. But I'm sure you are aware of that.

http://www.vcfed.org/forum/showthread.php?697 … r-a-286-Machine

Also, most IDE-CF cards have relatively poor sustained transfer rates vs a high end SCSI HDD

The IDE interface, especially pre-udma, is a limiting factor for cf-ide solutions. It will generally be very fast for typical system/boot drives though, since you almost never reach peak transfer rates for those use cases. Lots of random access of smaller files is really quick with cf cards. But there are also cf or sd to scsi solutions for the best of both worlds.

What you don’t like the whining noise of a 10,000 rpm SCSI drive ?
If you want quiet then go with the CF card.

Thats too complicated of a question to just say CF is faster, because its not always apples to apples. Also not all CF cards are fast CF cards. Also it depends on the interface not all IDE interfaces are fast, same with scsi. I can say with 100% certainty that Ultra 320 scsi with a good scsi drive is faster than PIO mode 4 IDE, even faster than UDMA 33. So if you are thinking that a CF card plugged into your mother board IDE 33 is faster than a U160 or even U320 in a pci slot on the same system with a 10k to 15k drive is faster you would be wrong.

If you have Ultra 133 PCI with your CF card plugged into that than thats a different argument but you didn't say that and I assume you didn't mean that. But on that note a Sata PCI with a SSD is faster than a CF.

A SSD to IDE is also faster than a CF.

CF isn't the king if you think CF is king I think thats wrong.

As for linear transfer speed, sd2scsi isn't terribly fast. It is narrow SCSI only.

The most common v5 version can reach 2.5MB/s max. A good CF card in CF to IDE adapter can do more, depending on controller, PIO/DMA mode, etc.

I plan to buy the SCSI v6 version which apparently supports synchronous transfers up to 10MB/s, but it is more expensive.

CF to IDE is hard to beat in terms of value. Cheap as chips, well supported and reasonably fast.

I personally prefer solid state media over any spinning head disk in my retro systems. Way more practical, reliable. Doesn't produce heat/noise...

derSammler wrote:

Any flash memory on IDE is faster than an SCSI drive..

appiah4 wrote:

I guess that depends on whether it's on plain old IDE or something like ATA100/133?

LunarG wrote:

The IDE interface, especially pre-udma, is a limiting factor for cf-ide solutions..

Warlord wrote:

Thats too complicated of a question to just say CF is faster, because its not always apples to apples.

😵 🤣 😐 😲 😈 😀 😘

Back to the original question.

Faster - SCSI or IDE-CF?

The answer is it depends.

Faster at what specifically? Raw sustained speed or random access?
Which SCSI device, controller, CF card and IDE controller are we comparing?

Unless we can specify that there can be no clear answer.

Intel486dx33 wrote:

What you don’t like the whining noise of a 10,000 rpm SCSI drive ?

Man up and turn up the music louder

SCSI HDDs have their own motor so they have the potential to be much faster than any CF/SD card which have no moving parts whatsoever.
If you throw them the light CF/SD card will be quicker to accelerate so it'll potentially get more initial speed than the comparatively heavy HDD from a single arm's swing. Still the greater mass of the HDD will make it gain more momentum so it'll be able to sustain speed longer than the CF/SD card.
When dropped in a vacuum they should all be equally fast.

Sorry.

CF on SCSI using an Acard bridge adapter.

Thanks for the information....

This is an old 386 DX-33. The SCSI Card is an Adaptec AHA-1522A currently. I think I am going to switch over to CF Card just for peace of mind that the drive wont suddenly crash as the drive is years old....

Smack2k wrote:

Thanks for the information....

This is an old 386 DX-33. The SCSI Card is an Adaptec AHA-1522A currently. I think I am going to switch over to CF Card just for peace of mind that the drive wont suddenly crash as the drive is years old....

my argument would be: "if the drive has survived this long without failing, it will likely keep going"

for just about everything after the ST-502 era, my experience has been that the vast majority of drive failures that aren't directly attributable to physical abuse, occur within the first 2-3 years of operation - if the drive has survived 10+ years I'd have a tremendous degree of confidence that it lacks manufacturing defects

True. However, a harddrive doesn't need to have a manufacturing defect in order to fail. It is full of mechanical parts that can simply get broken by means of operation. They will all eventually fail.

mpe wrote:

True. However, a harddrive doesn't need to have a manufacturing defect in order to fail. It is full of mechanical parts that can simply get broken by means of operation. They will all eventually fail.

of course, we all eventually die too, I just don't think it's a high likelihood outcome for the foreseeable future

maxtherabbit wrote:

of course, we all eventually die too, I just don't think it's a high likelihood outcome for the foreseeable future

Well... Not really.

This is actually a well-research problem (mean time to failure for hard drives). There is a phenomenon called "the bathtub curve". The likehood of failure actually significantly increases towards (or beyond) the end of life.

mpe wrote:

maxtherabbit wrote:

of course, we all eventually die too, I just don't think it's a high likelihood outcome for the foreseeable future

Well... Not really.

This is actually a well-research problem (mean time to failure for hard drives). There is a phenomenon called "the bathtub curve". The likehood of failure actually significantly increases towards (or beyond) the end of life.

Of course it does, but the question is: when is the end of life?

I think it is a wise preventative decision to switch out these older SCSI narrow drives before they fail. Their days are numbered. I've had so many eventually fail over the decades, even the drives I thought were reliable.

I've read varying reports of CF and SD cards holding data for around 10 years minimum, but is good for another decade once the data has been rewritten. I keep backup images of SD/CF hard drives.

I've been pleased with SCSI2SD v6 on an A2 microSD card, or ACARD-to-CF adapter.