I figure I'd share my experience, that it might help others trying to make sense of incomprehensible trouble in replacing their HDD with a CF card in older laptops.
In short, if CF to IDE doesn't work, just order a IDE SSD. 1.8" works and fits as a direct replacement for a 2.5" IDE HDD. If this answers your question, you don't have to read the rest of this. If you're interested, continue on.
I was working on restoring an HP OmniBook 800CT. I've decided I want to use it as my DOS through Windows 95 gaming laptop. The mechanical drive was failing, and I wanted to replace it with an IDE to CF adapter. I tried about six different CF cards and ran into all sorts of problems. Mainly, once a partition was created on the CF card, the laptop would not boot. Even from a floppy disk. It would just crash while trying to boot DOS.
I tried everything under the sun. Tried creating a 2GB partition for compatibility.
I tried several CF cards; 32GB, 16GB, 8GB, and 2GB.
Booting from a windows 95b floppy, I was able to see and partition the CF card.
Once a partition is created, you have to reboot. On reboot, the computer would crash while trying to boot dos from the floppy disk.
I did have limited success with a 2GB CF card out of an old Cisco router. It worked fine with dos 2.22, however wouldn't boot with windows 95 dos either by format /s or installed during the windows 95 setup process.
Finally, and I can't explain what went differently, I was able to get Windows 95 working on the 2GB CF card. However, the laptop still refuses to work with the larger cards.
When booting from the mechanical HDD into Windows 95, the computer was able to recognize the 32GB CF card inserted into a PCMCIA adapter, and had no trouble reading and writing from it.
Finally, my solution was to order a 32GB IDE SSD.
This is the drive I ordered:
https://www.amazon.com/gp/product/B0091SP8B8/
Yes, it is a "1.8" drive, however it fits in the same space as a regular 2.5, and the pins line up exactly, no trouble. The pin and socket connection is pretty tight, however you could stuff a small block of wood or something to make up the gap if you feel the laptop will be tossed around excessively. The screw holes on a 2.5" drive caddy will not line up, but again, I didn't find it that important. I'm probably going to put a dab of hot glue just for unnecessary certainty, and so it's easy to remove later.
I had absolutely no trouble at all installing Windows 95 on this drive and everything is working fine.
CF Cards are supposed to be totally IDE, EIDE, ATA, and UDMA, and ATA-PIO compatible. This laptop does support ATA-PIO mode 4 as per the service manual. Apparently there's something about CF cards that's not 100% completely compatible.
It should be noted that I was able to use these CF cards with an IDE adapter in my Dell Latitude CPi with no trouble, however it is a few years newer than the Omnibook. If you're wondering why I didn't pick the Latitude CPi as my dos-win95 gaming laptop, it's cause they're made out of lousy junky plastic that cracks all over the place. Even when it was new I had to replace the back plastic panel a few times cause it would just crack for no reason.
In short, if CF to IDE doesn't work, just order a IDE SSD. 1.8" works and fits as a direct replacement for a 2.5" IDE HDD. If this answers your question, you don't have to read the rest of this. If you're interested, continue on.
I was working on restoring an HP OmniBook 800CT. I've decided I want to use it as my DOS through Windows 95 gaming laptop. The mechanical drive was failing, and I wanted to replace it with an IDE to CF adapter. I tried about six different CF cards and ran into all sorts of problems. Mainly, once a partition was created on the CF card, the laptop would not boot. Even from a floppy disk. It would just crash while trying to boot DOS.
I tried everything under the sun. Tried creating a 2GB partition for compatibility.
I tried several CF cards; 32GB, 16GB, 8GB, and 2GB.
Booting from a windows 95b floppy, I was able to see and partition the CF card.
Once a partition is created, you have to reboot. On reboot, the computer would crash while trying to boot dos from the floppy disk.
I did have limited success with a 2GB CF card out of an old Cisco router. It worked fine with dos 2.22, however wouldn't boot with windows 95 dos either by format /s or installed during the windows 95 setup process.
Finally, and I can't explain what went differently, I was able to get Windows 95 working on the 2GB CF card. However, the laptop still refuses to work with the larger cards.
When booting from the mechanical HDD into Windows 95, the computer was able to recognize the 32GB CF card inserted into a PCMCIA adapter, and had no trouble reading and writing from it.
Finally, my solution was to order a 32GB IDE SSD.
This is the drive I ordered:
https://www.amazon.com/gp/product/B0091SP8B8/
Yes, it is a "1.8" drive, however it fits in the same space as a regular 2.5, and the pins line up exactly, no trouble. The pin and socket connection is pretty tight, however you could stuff a small block of wood or something to make up the gap if you feel the laptop will be tossed around excessively. The screw holes on a 2.5" drive caddy will not line up, but again, I didn't find it that important. I'm probably going to put a dab of hot glue just for unnecessary certainty, and so it's easy to remove later.
I had absolutely no trouble at all installing Windows 95 on this drive and everything is working fine.
CF Cards are supposed to be totally IDE, EIDE, ATA, and UDMA, and ATA-PIO compatible. This laptop does support ATA-PIO mode 4 as per the service manual. Apparently there's something about CF cards that's not 100% completely compatible.
It should be noted that I was able to use these CF cards with an IDE adapter in my Dell Latitude CPi with no trouble, however it is a few years newer than the Omnibook. If you're wondering why I didn't pick the Latitude CPi as my dos-win95 gaming laptop, it's cause they're made out of lousy junky plastic that cracks all over the place. Even when it was new I had to replace the back plastic panel a few times cause it would just crack for no reason.