Datafab MDCFE-SR Compact Flash reader notes

[Brutman]

There have been a few references to this device over the years and I was curious, so I bought one to test it out. Here are some quick notes.

Power: it definitely needs external power. Normally it expects to use a tap from the keyboard port, which of course we don't have on a PCjr. Mine was a later model that came with a USB power tap, so I connected that to a USB AC charger and used that. (One nasty side effect of having a newer model was not getting the DOS drivers on the CD, even though the CD was clearly labeled as having the DOS drivers. That's a different story.

Read/Write modes: My parallel port is bi-directional, and it found that with no special tricks.

Drivers: These are based on the EPST chipset from Shuttle, which is great - they made some great stuff back then. The documentation says that the /FLASH parameter is needed on EPATHD; I have no idea what it really does. It also suggests using /B for INT13 support, but that didn't seem to help with anything - I was not able to run FDISK as the docs implied I would be able to. In theory once you load EPATHD this is a SCSI device, so you can choose the removable SCSI drivers of your choice.

DOS 3.3 can only use 32MB FAT16 partitions. It got horribly confused when I inserted a CF card with a 512MB partition on it. DOS 5.02 was happy with anything. This is not unexpected.

Performance: On my PCjr with a NEC V20 and the bi-directional parallel port I was getting around 40KB/sec reads and writes on a 1MB file. So around 4x better than the floppy drive. The bottleneck is the parallel port obviously. If you don't have a bi-directional parallel port your reads will suffer.

Am I going to use this? Probably never. But the itch is satisfied. ;-0

[KenG]

I have one of them. Mine came with the use power cable but no drivers. I found them somewhere. This was my mass storage device and means to transfer files from a modern PC into the Jr. Now that I have the Jr-IDE, it will see less use. It should make a decent backup device though. I figured to dump data from the DOM to compact flash cards and then into my desktop PC. This does bring up a question though. The Jr-IDE seems to look for two devices. If I got an IDE cable, could I use an IDE card reader? That might give faster transfer rates.

[Brutman]

The BIOS on the jrIDE is seriously deficient, and that's my fault ...

- Don't run two drives on it. One drive works. A second drive - who knows. Until it is well tested data corruption is a real danger.
- Don't run non IDE drive devices on it. CF cards in an adapter should work as primary drives. If you are talking about a generic IDE card reader that reads multiple devices, don't bother.

[KenG]

Ok, thanks for the info. I will just stay with what I have. At least until Alan figures out his Rev.C with a Raspberry PI. That sounds very promising