Question regarding A1200 IDE bus

[Wain]

I read somewhere (don't remember where) that the A1200 was pushed into mass production with a few manageable bugs still in the system, the most major one being a lot of CPU taxation on the internal IDE bus.  

I was wondering if anyone knows if this issue was ever resolved, and how much more CPU usage are we talking about compared to IDE generated via a different controller(which has an already much higher rate of CPU taxation than SCSI).

[Jope]

It isn't really a bug per se, more like a cheap design descision..

I haven't used the internal ide in a long time, however, so I can't give numbers. :-/

[Piru]

I read somehwere (don't remember where) that the A1200 was pushed into mass production with a few manageable bugs still in the system, the most major one being a lot of CPU taxation on the internal IDE bus.

Non-DMA ide is like this, no way to get over it. This is not a bug, but a feature.

I was wondering if anyone knows if this issue was ever resolved

No it was never fixed.

With A600/A1200/A4000 IDE, all data goes thru 16-bit register. CPU need to push/pull each word one at a time. This is slow and CPU demanding.

[Wain]

It isn't really a bug per se, more like a cheap design descision..

I agree that something like that wouldn't really be a bug, just the thing I read made it sound like the engineering department really wanted a little more time to make the whole thing flow better, and were unhappy with having to go to production with it like that.

[Wain]

Okay, so it's unbuffered non-DMA IDE (eeewww), got it.

that's all I needed to know...

Thanks.

[ipino]

@ Wain

the IDE interface on A600/1200/4000 works *only* in PIO Mode 0, its maximum transfer rate would be 3.3 MB/s but most likely 2.3 MB/s is what you get...

This is why there are some "cards" that plug on a particular chip (don't remember its name) in the A1200 and provides UDMA modes

/ipino

[Framiga]

@ ipino

if you are speaking about the PowerFlyer cards, they aren't UDMA but E-IDE with PioMode4 and eats more CPU power, than internal IDE. (anyway, are very useful and fast)

Ciao

[mikeymike]

This is why there are some "cards" that plug on a particular chip (don't remember its name) in the A1200 and provides UDMA modes

I was under the impression due to recent conversations on forums here that UDMA was not possible with any hardware add-ons, end of story...

I'll try and dig out the thread.

[Karlos]

What about UDMA capable IDE drives attached to an accelerator card's SCSI adaptor via a bridge?
Does that still work in DMA mode?
If so, where can I get the cabling and bridge? :lol:

[Piru]

What about UDMA capable IDE drives attached to an accelerator card's SCSI adaptor via a bridge?

Works fine. I have two SCSI2 AEC-7720U SCSIDE modules in my A1200 connected to BlizzPPC SCSI.

Does that still work in DMA mode?

Yes, of course.

If so, where can I get the cabling and bridge?

ACARD SCSIDE. At least KDH is selling them.

No special cables are required, normal SCSI cables will do.

This is no longer A1200 IDE bus, however. So it's abit OT.

[Karlos]

I was just reflecting on mikeymikes remark.

Piru wrote:

No special cables are required, normal SCSI cables will do.

I was actually thinking about that awkward connector on the card itself :-)

This is no longer A1200 IDE bus, however. So it's abit OT.

Granted, but I was reflecting on mikeymike's post about no UDMA IDE solutions for A1200 you see...