8bitbubsy wrote on 2022-07-14, 11:26:

So, does it make sense to use the new 286 driver on a 486DX4-100? Will it work and give faster speeds?

Even if Retro Eric answered 😀

I would like somebody to try, because in theory, it should work.
You may need to add a value in the delay.

In the 286 version of the driver, I did remove the delay function only where it was not necessary.
And the 286 code is the fastest possible (Even for 486)

The overall performance is of course limitted by the ISA Bus speed and we know it is not that fast.

8bitbubsy wrote on 2022-07-14, 11:26:

So, does it make sense to use the new 286 driver on a 486DX4-100? Will it work and give faster speeds?

Absolutely it does, and if you are using the Lo-tech card it will give you much better throughput due to 1) the port mapping enabling 16-bit IO (rep insw) and 2) the ZWS option. It will need testing as I'm not sure if the loop unrolling specifically provides for a delay between packets (I haven't seen the code) that I suppose we could run in to.

EDIT: I see FreddyV already noted the same, sorry. The performance limit will be both ISA bus derived and the fact that the USB itself runs at only 12Mbps. But for reference, the Lo-tech 8-bit CF board can hit 1.2MB/s on a 12MHz 286 and can go higher on 486/Pentium, I think about 1.8MB/s was the limit. It's been a while since I tried one in that configuration. But anyway, the USB board will never deliver more than 1.5MB/s due to the USB bus speed itself.

So, some of you tested and did not tell me 😀
I have a 386, some 486, Pentium, Pentium 3, but lasy to test on them.
I concentrate more on the 8086/286 for the moment

The way the CH375 Chip is done also limit everything.

This chip has a 64Bytes buffer, so we need to send another read command and wait the end of the transfer, after each block of 64 Bytes.
Then, we need to add the time of the transfer to the CH375, then the transfer time to the ISA Bus and the "Fast" code doing the transfer is only for these 64bytes.

What I think is that this solution is competitive and can definitely replace an XTIDE (When boot will be available), Up to a 286.
for >286, it will never beat a CF, or IDE in performance, but it is an excellent solution to transfer files.

What is nice with this chip is that it is extremely simple to do a parallel port board/Version and update the driver > Can replace the Parallel ZIP solution as well.

Is it possible to hack the non-LoTech board to enable 16-bit I/O? Or would that require a 16-bit ISA connector?

The board will have ISA A0 routed somehow to the CH375 pin 8 (A0). That connection would need to be cut and a jumper wire run from CH375 pin 8 to ISA A1 instead. The ZWS function is dependent on additional logic.

@FreddyV = decomp is ok. Anyway they have all the examples including sources here. USB HID, Midi, etc: https://www.wch.cn/bbs/thread-65122-1.html

For tech support, you can mail this guy directly: mj@wch.cn (or tech@wch.cn). I bought random card USB ISA from AliExpress and it just contains the WCH (CH375) chip, so then you contact the manufacturer of the chip. That's what I did. It does not matter, who made the PCB (Lotek or Ali). By default Ali don't have the BIOS EEPROM included, but you can just buy EEPROM, write it, and put into socket (that's what the jumpers are for).

My main interest is ZIP 750MB (USB only) or ZIP 250MB (USB version) to get working on 486 that has ISA only slots. Current workaround would be to get SCSI ISA card and connect ZIP 250MB to it and hope that ZIP750 vs ZIP250 compatibility works well.

cyberluke wrote on 2022-07-17, 07:43:

For tech support, you can mail this guy directly: mj@wch.cn (or tech@wch.cn). I bought random card USB ISA from AliExpress and it just contains the WCH (CH375) chip, so then you contact the manufacturer of the chip. That's what I did. It does not matter, who made the PCB (Lotek or Ali). By default Ali don't have the BIOS EEPROM included, but you can just buy EEPROM, write it, and put into socket (that's what the jumpers are for).

The ALI express board ROM Does not work, there A18 and A19 @ lines are not connected.
This board is bugged...

cyberluke wrote on 2022-07-17, 07:47:

My main interest is ZIP 750MB (USB only) or ZIP 250MB (USB version) to get working on 486 that has ISA only slots. Current workaround would be to get SCSI ISA card and connect ZIP 250MB to it and hope that ZIP750 vs ZIP250 compatibility works well.

The ATAPI version works great on my 386 even though the bios knows nothing about it. Load the ATAPI driver and run guest... Any reason you didn't go that route?

flynnsbit wrote on 2022-07-17, 11:44:

cyberluke wrote on 2022-07-17, 07:47:

My main interest is ZIP 750MB (USB only) or ZIP 250MB (USB version) to get working on 486 that has ISA only slots. Current workaround would be to get SCSI ISA card and connect ZIP 250MB to it and hope that ZIP750 vs ZIP250 compatibility works well.

The ATAPI version works great on my 386 even though the bios knows nothing about it. Load the ATAPI driver and run guest... Any reason you didn't go that route?

Because this is special Dell Optiplex 486 and I already have only two 5.25'' slots. One is Pioneer DVD-ROM in-slot drive, second is combined floppy 5.25'' + 3.5''. There is no other space in the case. That's why. On 386DX I have this Atapi drive, yes. But here, I need external solution via SCSI or USB.

Can I use one of these as a secondary disk that I can access from windows 3.11 or 95 that is booting from a internal hard drive?

Also, where is the best place to buy these? Are there more than one version?

alexanrs wrote on 2015-05-12, 14:05:

USB 1.0 isn't THAT useless. I've used flash drives on Socket 7 + USB1.0 systems before, and it is still faster and more convenient than floppies (specially because my main PC doesn't have a floppy drive... or controller). Network is still king though.

USB 1.x was also good for printing. It was a significant improvement over LPT. I used to have hp 959c with both LPT and USB inputs. When printing text (e.g. PDF) in high quality mode, the printer was actually faster than LPT could allow. Which means it had to pause every so often waiting for more data. No such problem with USB connection.

When I first got back into retro I was all obsessed with trying to get usb 3.0 on these computers. (Which you can do btw if it has pci)

Anyway, after getting some experience it turns out that actually usb 1.0 or 1.1 is better because the 2.0 cards slow the system down even when not in use. If the system has onboard usb then just get a internal hub.

Adding More USB Ports to Retro Motherboards

But non pci systems can be a challenge.

Re: ISAPC-00 ISA-to-PCMCIA card

Btw^ another possible usb isa route?

Sphere478 wrote on 2022-07-19, 20:09:

Can I use one of these as a secondary disk that I can access from windows 3.11 or 95 that is booting from a internal hard drive?

Also, where is the best place to buy these? Are there more than one version?

I’m not sure if anyone has tested the alpha BIOS or driver(s) under Windows yet. But they are just Int13h handlers at the end of the day so should work.

There are two main versions of the ISA USB PCB built on the CH375 currently:

1. the eBay type, which ships from numerous suppliers and has socket for an option ROM. The option ROM is however not usable as some of the required address lines are not presented to the chip. Therefore this can be used with a driver or the option ROM stored elsewhere.

2. The Lo-tech ISA USB (my board), which addresses the ROM problem and provides better performance and PC/XT Slot8 compatibility.

Since the driver and BIOS has taken a few years to get working, the Lo-tech board (formerly sold as a prototype) has since sold out. However, as there seems to be interest in this I will likely bring this back via TexElec with a few refinements and a variant for later machines.

Hope that helps.

OK if you find any spares laying around hit me up it sounds like yours is the one to get will these usb isa disks be plug and play in windows? Or would they require a reboot?

pearce_jj wrote on 2022-07-19, 22:44:

1. the eBay type, which ships from numerous suppliers and has socket for an option ROM. The option ROM is however not usable as some of the required address lines are not presented to the chip. Therefore this can be used with a driver or the option ROM stored elsewhere.

Is there a ROM for the eBay type that will let me use the USBISA card (e.x. boot, or use without a driver)? Could I then use the ROM on my Ethernetcard with a ROM socket?
Is there an XT-IDE ROM that has support for both the XT-IDE and USBISA (no driver needed).

The idea is to add the support for it to the XTIDE Universal BIOS.

Oh cool! So just a new version of the xt-ide binary and it’s ready to go?