Compact flash woes

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Joined: Fri Aug 06, 2021 2:10 pm
Favorite Palmtop: HP100LX

Compact flash woes

Post by jhhoward »

I have a small collection of DOS palmtop computers: an HP 100LX, a Sharp PC-3000 and a clone of a Tidalwave PS-1000
I use a compact flash adapter and 32MB compact flash cards, to store data and easily transfer files between my modern PC and the palmtops. I also have a single 256k SRAM card which came with one of the palmtops when I purchased it.

To get the cards working:
- The HP 100LX, the compact flash cards worked out of the box.
- The Sharp PC3000 needs the SUNDRV driver (archived here: ... re-support)
- The Tidalwave clone needs the MM_ATA.SYS driver ( ... ve-palmtop). I also had to take the compact flash adapter out of its metal case to make it physically fit in the Tidalwave's slot.

Everything was working fine with two 32MB compact flash cards - I was able to copy files from my modern PC using a USB to compact flash adapter, and run programs on the three different palmtops. At some point, one of the cards became unreadable, which I had assumed was due to its age. Then the other card stopped working too. They seem to now be in a strange state where I am able to reformat the cards and use them on the modern PC (via USB adapter) and a Windows 98 laptop (using the laptop's PCMCIA port) but they remain unusable for the palmtops. Previously I was able to reformat them on the palmtops themselves but they are no longer recognised by the hardware. My current theories are:
- Maybe a dodgy USB port on the modern PC, as I've previously noticed devices disconnecting / reconnecting. Perhaps this happened during a write and corrupted the cards?
- The Tidalwave was the most recent purchase of mine so maybe the MM_ATA.SYS driver corrupted something?
- The Sharp PC3000 and Tidalwave both like to drain through AA batteries quickly so may have died with the compact flash cards still inserted. Hasn't been a problem with the Sharp before but the Tidalwave is newer so a possibility.

I have just purchased a new 4MB compact flash card which seems to be working fine. Before I start using it properly (and potentially corrupt it again) is there a way to dump any additional metadata from the card? Maybe the 32MB cards have had some metadata / system level flags corrupted but can be recovered somehow?

So an interesting observation: when I plug in the working 4MB card into my Windows 98 laptop, the PCMCIA service describes it as 'SanDisk ATA FlashDisk' but when I try with the (not working on palmtops) 32MB card, it reports it as 'Standard IDE/ESDI Hard Disk Controller'
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Joined: Fri Feb 17, 2023 4:40 pm
Favorite Palmtop: HP200LX

Re: Compact flash woes

Post by ArchiMark »


Been awhile since you posted....

We have a very similar palmtop collection!

I have a HP 200LX (8MB/doublespeed), Sharp PC 3100 and Tidalwave PS-1000 (might be a clone, but not labeled...).

Just received the Sharp and Tidalwave.

Trying to get a 2MB Pretec SRAM card (SN5002) working on these little guys but so far no go.....

I want to be able to use the SRAM card on Sharp and Tidalwave so that I can transfer the driver files to them in order to use CF cards on them.

Any suggestions regarding getting SRAM card working on these palmtops?


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