Datafab MDCFE-SR Compact Flash reader notes
Posted: Sun Nov 06, 2016 2:27 pm
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
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