DH> It's much better than the current Amiga parallel port. Not surprising,
DH> really, given the Amiga parallel port is just a _slower_ C64 user port
DH> using the standard PC parallel pinout. The 8520 is just a modified 6526,
DH> a design from the 70s.
Hmm.. So even the C64 had better throughput than the Amiga on the equal port? (Userport vs Par-port)
DH> Real EIDE is faster than fast synchronous, 8-bit SCSI-2. EIDE tops out
DH> at around 13.5MB/s, FS SCSI-2 at 10MB/s (that's A4091 and A4000T),
DH> regular synchronous SCSI at 5MB/s (that's A3000 on down).
There has been rumors about SCSI-3. Can you give me some better info about that interface. When it will show up for us common people and some data on it?
>> There is a new BIOS available for PC's that gives EIDE the possability of
>> 8 attached HD's,
DH> Nonsense -- the selection of disks on the IDE/EIDE bus is a hardware
DH> control feature. You can, in some circumstances, split the bus in two.
DH> There's a hack for the A4000 that takes its one IDE bus and splits it
DH> into two separately addressed buses. That's fairly easy, based on the
DH> way the A4000 implemented IDE, but it's far less likely to work on a PC,
DH> where the IDE bus is driven in limited I/O space, rather than via memory
DH> mapping. On any given IDE bus, you can have one master device and one
DH> slave device, period. This is a feature of the devices themselves; there
DH> is no intelligence in the IDE bus itself, it's all in the devices
DH> (historically, IDE evolved as a subset of the PC-AT bus -- the idea was
DH> that you would put the hard disk controller in the drive, and just run
DH> the AT bus to the drive).
>> and a stunning top performance on HD's at 200MB/second.
DH> Bunk. The official limit on EIDE is 13.5MB/s. You might be a tad faster
DH> than that with selected drives, but not significantly so. The 16-bit
DH> datapath, TTL signalling, the quality of the cable, and the layout of
DH> the IDE signals on the cable all set upper limits on what you can manage
DH> with the protocol.
Maybe I should have added that this was something I heard from a PC owner and that it most likely was a rumor? (It seems that PC owners generally don't like SCSI for some reason.)
DH> There isn't as PC with a CPU to EIDE connection that fast, regardless of
DH> whether the drive, cabling, etc. would support it. Keep in mind that the
DH> 32-bit PCI bus, which was designed very carefully to support high speed
DH> transfers, is limited to a peak of 132MB/s.
Hmm.. Maybe he meant 20MB/second?
DH> Like I said, EIDE is already faster than SCSI, until you go to 16-bit or
DH> Fast-20 SCSI. In either case, it's faster than any single drive
DH> available today, though of course bursts from drive cache may actually
DH> run at the full speed.
OK.. Info assimilated. :)
DH> In fact, the A4K/A1200 IDE interfaces are the slowest form of plain IDE.
DH> Generic IDE can go faster, EIDE faster than that. Realize them for what
DH> they are: kludges. The IDE bus was a requirement for the A4000 because
DH> management forced it to be, and it was added as well as it could have
DH> been considering it wasn't planned for in the A3000 architecture (upon
DH> with the A4000 is based). The IDE in the A1200 was necessary to support
DH> some kind of hard disk, in a low-end machine, for as little incremental
DH> cost as possible. That's what IDE is for. And it still is: EIDE can give
DH> you better-than-SCSI performance for little additional system cost.
DH> That's why every PClone uses it, few ship with SCSI even through SCSI is
DH> superior to EIDE as far as the device supports go.
Mmm.. Will the EIDE interface in the Walker manage >10MB/second with some form of accelerator in it? (I guess the EC030/40 won't give that kind of performance.)
DH> IDE and EIDE both support two devices per bus. It was common to have one
DH> IDE bus in IDE systems, and it's recently become popular to offer two
DH> EIDE buses in EIDE systems. But nothing has changed the basic design:
DH> one master, one slave per bus.
IMHO - That s*cks. Why can't the engineers do something new? A new and better interface. Or is that to difficult? You are a h/w engineers. What are the problems with constructing a new/better HD-interface?
(Thanks for making such a great util like DiskDalv. I recently registered
