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SD Card Adapter On an Old 386

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First post, by fsmith2003

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Just curious if anyone here knows what the correct specifications are when using a SD Card adapter on an old machine? The kind where you have to manually input the cylinders, heads, sectors, size etc. in the bios.

Reply 1 of 23, by PhilsComputerLab

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I use one in my 386. You use it like a standard IDE device. It auto detects if your BIOS support it, but you can enter manual settings also.

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Reply 4 of 23, by matze79

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Cylinder depends on Size of SDCard ... Heads 16, Sectors 63..

128Mb SDCard 245-256 Cylinder..
256Mb SDCard 490-512 Cylinder...
2Gb SDCard 4096 Cylinder..

just try.. My BIOS does not like setting maximum possible cylinder.
most SDCard Adapters are using SD2CF Chip. So its really a SD to CF Adapter with IDE Connector

i would recommend CF Cards or DOM's. Because they can write parallel.
SDCards are Serial SPI Protocol.

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Reply 5 of 23, by jesolo

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Where I have an older 286 or 386 PC with a BIOS that is not able to auto detect the "parameters", I temporarily insert the adaptor and media (SD card or Compact Flash) into a later generation PC that does have a BIOS that is able to auto detect the "parameters". They normally list the CHS, LBA & "Normal" parameters. I then write these down and manually type them in in the CMOS setup of the older PC. Either use the CHS or "Normal" parameters, since it won't be able to translate using the LBA parameters.

Just take note that older BIOSes in 286 & 386 PC's are normally limited to 504 MiB or 528 MB (depending on how you calculate it). So, regardless of the size of your storage device (SD card), the BIOS will only be able to read up to this maximum limit. In such a case, you can just insert the following parameters: 1024 cylinders, 16 heads & 63 sectors (you can reduce the cylinders to 993, which is what my BIOS has picked up as the setting for my 512 MB Compact Flash card). Using the maximum cylinders of 1024, this should then give you a total capacity of 528,482,304 bytes = 504 MiB (or 528 MB).

However, this would be a waste of the available storage space. To overcome this you can either use Dynamic Drive Overlay (DDO) software or, you can plug in a network card with a Boot ROM socket, flash an EEPROM chip with the XT-IDE BIOS and then let that BIOS "take over" the function of the main BIOS (in terms of hard drive parameters).

Just bear in mind that DOS (up to 7.0) is limited to a maximum partition size of 2 GB (you can create multiple partitions).

Reply 6 of 23, by matze79

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Caldera OpenDOS aka DrDOS can use FAT32 with latest patches, so you can overcome this limitations 😀

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Reply 8 of 23, by zerodiagonal

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If you'd like to give it a go, here's a little program that I've found some time ago but have't really had a chance to test it as I'm constantly postponing buying an adapter... http://kevparr.com/misc/whatide.php (there's a link to an interesting video, with details).

Reply 9 of 23, by Ampera

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matze79 wrote:

Caldera OpenDOS aka DrDOS can use FAT32 with latest patches, so you can overcome this limitations 😀

It's been debated many times on this forum, but my personal opinion is the same. There is no reason to use a FAT32 partition on DOS. All it does is break programs, and cause issues. If you need more than 2GB, then you shouldn't be using DOS in the first place, you should be using Windows. My 486 has a 2GB WD Caviar and I barely use a quarter of it with a load of games stuffed on there (Like 4 copies of Doom, k?)

Reply 10 of 23, by fsmith2003

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zerodiagonal wrote:

If you'd like to give it a go, here's a little program that I've found some time ago but have't really had a chance to test it as I'm constantly postponing buying an adapter... http://kevparr.com/misc/whatide.php (there's a link to an interesting video, with details).

zerodiagonal - That program worked great! Thanks for the suggestion. It did exactly what I needed it to and I was able to obtain all the information for my SD-IDE Adapter to get it booted into DOS. Problem Solved!

Reply 11 of 23, by iFXBR

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Help guys! I am trying to use an SD2IDE adapter on my 386DX40 (ABIT 386 AT3 motherboard/Winbond Multi IO) computer and it does not work! I tried CF2IDE as well, without any success. I think that my Multi IO card can be the problem.

When I try to autodetect my harddrive by using SD2IDE adapter, it just does not work. I connected it on another computer and it is detected perfectly. Then I took note of CHS info and configured on 386 manually. Now the 386 seems to accept the SD2IDE adapter - Time to FDISK and FORMAT the 1GB SDCARD: FDISK runs perfectly, but when I try FORMAT I got "Invalid drive specification" error message.

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Reply 13 of 23, by fsmith2003

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Try to write 0000 to it on the a modern pc and then on the 386 do a fdisk to add the partitions and then do a fdisk /mbr to replace the mbr.

Reply 14 of 23, by jesolo

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iFXBR wrote:

Help guys! I am trying to use an SD2IDE adapter on my 386DX40 (ABIT 386 AT3 motherboard/Winbond Multi IO) computer and it does not work! I tried CF2IDE as well, without any success. I think that my Multi IO card can be the problem.

When I try to autodetect my harddrive by using SD2IDE adapter, it just does not work. I connected it on another computer and it is detected perfectly. Then I took note of CHS info and configured on 386 manually. Now the 386 seems to accept the SD2IDE adapter - Time to FDISK and FORMAT the 1GB SDCARD: FDISK runs perfectly, but when I try FORMAT I got "Invalid drive specification" error message.

You're using a 1 GB SD card on a BIOS that most likely has a 528 MB limit (refer my earlier post).
Insert the parameters for a 528 MB drive and see what happens.

Reply 15 of 23, by feipoa

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Seems that this number varies because of how some BIOSes interpret what a kilobyte is (e.g. 1KB = 1000 bytes, or 1KB = 1024 bytes). Not knowing what scheme my BIOS uses, I set the HDD size as 503 MB to be safe. 976 cylinders, 16 heads, 63 sectors. When I use my CF card in another 386, it reports it as 480 MB, so my original guess was a bit too conservative.

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Reply 16 of 23, by iFXBR

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jesolo wrote:
iFXBR wrote:

Help guys! I am trying to use an SD2IDE adapter on my 386DX40 (ABIT 386 AT3 motherboard/Winbond Multi IO) computer and it does not work! I tried CF2IDE as well, without any success. I think that my Multi IO card can be the problem.

When I try to autodetect my harddrive by using SD2IDE adapter, it just does not work. I connected it on another computer and it is detected perfectly. Then I took note of CHS info and configured on 386 manually. Now the 386 seems to accept the SD2IDE adapter - Time to FDISK and FORMAT the 1GB SDCARD: FDISK runs perfectly, but when I try FORMAT I got "Invalid drive specification" error message.

You're using a 1 GB SD card on a BIOS that most likely has a 528 MB limit (refer my earlier post).
Insert the parameters for a 528 MB drive and see what happens.

Already tried, no success. In fact I tried even fixed values present in BIOS, like HD type 1 (10MB).

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Reply 17 of 23, by iFXBR

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fsmith2003 wrote:

Try to write 0000 to it on the a modern pc and then on the 386 do a fdisk to add the partitions and then do a fdisk /mbr to replace the mbr.

I plugged it on my 486DX 100MHz and wrote successfuly. When I plug it back to 386, FDISK report the partition correctly but MS-DOS does not see C:

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Reply 19 of 23, by matze79

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It's been debated many times on this forum, but my personal opinion is the same. There is no reason to use a FAT32 partition on DOS. All it does is break programs, and cause issues. If you need more than 2GB, then you shouldn't be using DOS in the first place, you should be using Windows. My 486 has a 2GB WD Caviar and I barely use a quarter of it with a load of games stuffed on there (Like 4 copies of Doom, k?)

No, but some Games eat up more then 100 Mb each.
Also storing CD-Images for use with Emulation Driver is a nice option to have.

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