Anyone interested how fast the 60 GB 1,8" Toshiba hard drive is? I must admit that I'm positively surprised. It easily outperforms any period correct drive from socket 7 era and perhaps from super socket 7 era as well.
I installed last of my HDD-CF-drives to my 486DX4 system (I had to disassemble it completely before I was able to install it) so it was a good change to test few different drives with HDD Speed. Here are some results. It is a text file saved with HDD Speed 2.1.
Here are the drives found in the result file:
160 GB SAMSUNG SP1634N (I replaced this with my HDD-CF-drive)
6 GB Hitachi microdrive HMS360606D5CF00 (this is one of the microdrives I like so much)
60 GB TOSHIBA MK6006GAH (this is the 1,8" HDD)
1 GB Seagate ST51080A (highend IDE drive from 1995, so likely the best period correct drive for my DX4 system)
6 GB Seagate ST36531A (typical super socket 7 era drive)
500 MB QUANTUM MAVERICK 540A (one of period correct drives for 486DX2 systems with 500 MB BIOS limit)
130 MB Seagate st3144AT (this came with Copam)
First note that the transfer rates are not fully comparable between all drives. The test uses old BIOS INT 13h functions to test the drives and this means maximum of 8 GB can be accessed. For drives larger than this the minimum transfer rate is incorrect because the slowest area of the drive cannot be accessed by old INT 13h functions. But if you are going to use DOS versions with only FAT16 support, then the slowest is the slowest you are actually going to get. But for FAT32 supported DOS versions (FreeDOS, Windows 9x) that transfer rate is not the real minimum. It is the transfer rate at around 8 GB and for that 160 GB drive, for example, that is pretty much still at the beginning of the drive so at the fastest area.
But does that even matter? For those large drives PIO4 will be a bottleneck even at the real end of the drive.
I have another thing to note. I'm not sure what kind of transfer rates you are used to for 486 VLB systems. My DX4 system has a VLB multi I/O card with Vision QD6580 IDE controller and XTIDE Universal BIOS has support for it so best PIO mode supported by the drive will be used and 32-bit transfers between CPU and I/O card (the VLB IDE controller buffers the data so 32-bit CPU instructions can be used).
So the pleasant surprise was that the 1,8" HDD has the best transfer rate, over 10 MB/s!!! I don't know why it is that fast, the 160 GB Samsung I've been using on the DX4 system only reads 6,8 MB/s and I was under impression that it would be the max I can get since PIO4 already limits the drive. So the Toshiba 1,8" drive has excellent PIO transfer rates! Very good for retro computers.
But perhaps more important it the seek times. CF cards have practically no seek times and that is one reason why they are popular solutions for retro computers. Toshiba has average seek time of 6,3 ms and average access time of 14,1 ms. The 160 GB 7200 rpm drive is naturally faster: 4,3 and 9,1. As expected, small silent 1,8" HDD cannot seek that fast. Also note that the 8GB old INT 13h limit affects these seek results just like transfer rates so not much seeking is needed when accessing only the beginning of the drive but for FAT16 DOS versions that is what you actually get.
Lets compare 6GB drives next, the Hitachi microdrive and old 6GB Seagate HDD. Microdrive is slow: 12,8 and 21,7. It puts it to about same speed as 500 MB hard disks so it is good if you want period correct access times but larger capacity. 6GB Seagate HDD has average seek time of 9,8 ms and average access time of 16,3 ms. So it is slower than the 1,8" HDD. It has only 128k cache but it is almost enough to get transfer rates comparable to 160GB Samsung, but no where near the fast 1,8" Toshiba.
What about older drives? The 1GB period correct (for my DX4 system, not Copam) highend Seagate IDE drive is simply slow (and noisy). At least it has better access times than the microdrive but transfer rates are no where near the PIO4 limit even though the drive support PIO 4. But the transfer rates are a lot better that what ISA multi I/O card would be capable of.
One thing to note about even older drives. The 500 MB Quantum and the 130 MB Seagate are both so slow that VLB controller is completely useless. This kind of performance is reachable with ISA multi I/O controller.
This post was not very Copam related but I think it had good information about when VLB multi I/O is needed (only the IDE controller uses the VLB extension, not the other stuff in it) and that the 1,8" HDD is actually a very good drive for retro computers. I'll benchmark the 1,8" HDD on a Copam later for comparison. The Copam does not have VLB IDE controller so performance will be limited by ISA.