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386 does not boot from compact flash

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First post, by AlessandroB

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I have an IBM PS/1 that detects compact flash up to 512MB which I can't get to boot, the machine starts with the 6.22 install floppy, it installs correctly but then once I reboot it does the whole process of boot until the os is loaded and stays with black screen… anyone have any idea why?

Reply 1 of 21, by vstrakh

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The issue can lie in the Compact Flash adapter, grounding the pin 28 which carries ALE signal from ISA bus.
Some cards may work ok with just front edges of the ALE signal (the length of IDE cable gives some nanoseconds), the other will not.

Of course, this is just a hint based on CF being used in pre-ATA spec hardware. The actual issue could be something totally different.

Reply 3 of 21, by vstrakh

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AlessandroB wrote on 2023-06-18, 07:26:

it does the whole process of boot until the os is loaded and stays with black screen…

How do you know the os was loaded?

Reply 4 of 21, by zapbuzz

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AlessandroB wrote on 2023-06-18, 07:26:

I have an IBM PS/1 that detects compact flash up to 512MB which I can't get to boot, the machine starts with the 6.22 install floppy, it installs correctly but then once I reboot it does the whole process of boot until the os is loaded and stays with black screen… anyone have any idea why?

Back in the day i only used 64mb - 128mb mechanical disks on my 386 without problems. if the disk was too big it would still display but not work properly.
I used to look for motherboards with built in IDE controller for 386 to install the dynamic drive overlay but ended up with a SCSI setup instead.
black screen just means hung system.

So to get the 512mb cf flash working i'd use a scsi card interface with a scsi to cf card adapter for extra capacity support by the scsi BIOS not the motherboard.

Reply 6 of 21, by AlessandroB

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vstrakh wrote on 2023-06-18, 09:10:

The issue can lie in the Compact Flash adapter, grounding the pin 28 which carries ALE signal from ISA bus.
Some cards may work ok with just front edges of the ALE signal (the length of IDE cable gives some nanoseconds), the other will not.

Of course, this is just a hint based on CF being used in pre-ATA spec hardware. The actual issue could be something totally different.

same problem with two different adapter and with a CF Sandisk 512mb and with one IBM Microdrive 340mb.

Reply 7 of 21, by AlessandroB

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zapbuzz wrote on 2023-06-18, 11:25:
Back in the day i only used 64mb - 128mb mechanical disks on my 386 without problems. if the disk was too big it would still di […]
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AlessandroB wrote on 2023-06-18, 07:26:

I have an IBM PS/1 that detects compact flash up to 512MB which I can't get to boot, the machine starts with the 6.22 install floppy, it installs correctly but then once I reboot it does the whole process of boot until the os is loaded and stays with black screen… anyone have any idea why?

Back in the day i only used 64mb - 128mb mechanical disks on my 386 without problems. if the disk was too big it would still display but not work properly.
I used to look for motherboards with built in IDE controller for 386 to install the dynamic drive overlay but ended up with a SCSI setup instead.
black screen just means hung system.

So to get the 512mb cf flash working i'd use a scsi card interface with a scsi to cf card adapter for extra capacity support by the scsi BIOS not the motherboard.

I have 128mb CF but i haven’t tried because is very small, even for dos gaming. I will try before follow the scsi route

Reply 8 of 21, by AlessandroB

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Now I explain why I want to use a compact flash, I have many ide disks, and on this IBM ps/1 I have a beautiful 300mb ibm ide disk that works great.

I'm trying to use a compact flash as big as possible because I want to have a simply detachable support, in order to put the cf card in all my IBM systems: 5150, ps/2 286, ps/1 386, 486, pentium 1, PentiumII /III, Pentium4. Basically when I test a game I want to both test on all these platforms and move the same disk with all the same configurations to all my systems easily and quickly. the ideal would be to use at least a 1gb cf, from 486 onwards it should see it, the problems come with the 5150,286,386.

Reply 9 of 21, by vstrakh

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AlessandroB wrote on 2023-06-18, 12:18:

same problem with two different adapter

Then it's either not CF fault, or both adapter has the same issue with ALE signal.
A lot of adapters are made for ATA specs in mind, like Socket 7 motherboards with onboard IDE controllers, where the pin 28 is already grounded on the controller side for Cable Select function.
But it's not the case for old IDEs, where multi-i/o card just passively passing through the ISA bus ALE signal into the IDE cable.
Look at the CF-IDE adapter's IDE connector pins where they're soldered. if the pin 28 is grounded directly at the pcb, connected to neighboring GND pins - that adapter will cause issues for old IDE setups, even if the system is seemingly booting ok.

Also, how do you know the system has booted?

Reply 10 of 21, by AlessandroB

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vstrakh wrote on 2023-06-18, 13:05:
Then it's either not CF fault, or both adapter has the same issue with ALE signal. A lot of adapters are made for ATA specs in m […]
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AlessandroB wrote on 2023-06-18, 12:18:

same problem with two different adapter

Then it's either not CF fault, or both adapter has the same issue with ALE signal.
A lot of adapters are made for ATA specs in mind, like Socket 7 motherboards with onboard IDE controllers, where the pin 28 is already grounded on the controller side for Cable Select function.
But it's not the case for old IDEs, where multi-i/o card just passively passing through the ISA bus ALE signal into the IDE cable.
Look at the CF-IDE adapter's IDE connector pins where they're soldered. if the pin 28 is grounded directly at the pcb, connected to neighboring GND pins - that adapter will cause issues for old IDE setups, even if the system is seemingly booting ok.

Also, how do you know the system has booted?

because is doing the memory check, and a “bip!”

Reply 11 of 21, by vstrakh

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That's the only the POST sequence, not "os loaded".
The more likely issue now is that you don't have the Master Boot Record initialized, the piece of code that must be located on the first sector of HDD/CF. It will scan the partition table for active partition, then read the OS boot sector and pass control to it.
If MBR is not there - nothing will be booting the os. Hence the advice to install the MBR with 'fdisk /mbr' command.

Reply 12 of 21, by AlessandroB

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vstrakh wrote on 2023-06-18, 16:49:

That's the only the POST sequence, not "os loaded".
The more likely issue now is that you don't have the Master Boot Record initialized, the piece of code that must be located on the first sector of HDD/CF. It will scan the partition table for active partition, then read the OS boot sector and pass control to it.
If MBR is not there - nothing will be booting the os. Hence the advice to install the MBR with 'fdisk /mbr' command.

But why? i install DOS with the diskette like i do in regular hard disk, and always work and boot.

Reply 15 of 21, by Deunan

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I've had issues installing DOS on both CF cards and HDDs, I think it can get confused if there is already a bootloader in MBR but it's not DOS-compatible. Then the installation process will refresh the partition table but not the code.

Reply 16 of 21, by HenriWintermans

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I had the same issue with my old 486DX-33 machine. It would actually work fine with some SD cards I had, but not with any of my CF cards (that are supposed to be less problematic). I made a boot disk with FDISK on it, I created the DOS partition on the CF card with FDISK, formatted it with /s, then ran FDISK /mbr, and then it started booting from it just fine.

I also had a separate issue of the BIOS recognizing the cards properly since it has no auto detection, so I used IDEINFO on a newer computer to determine the numbers to be entered.

I would make the partition slightly smaller, around 500 MB. Originally, I made the mistake of having a 1 GB FAT16 partition. DOS 6.22 and Windows 3.11 seemingly recognized it, but refused to write on or read from a big chunk of the partition. Technically DOS 6.22 can handle up to 2 GB FAT16 partitions, but BIOS limitation may cap it at 504 MB, like it was in my case.

Reply 18 of 21, by Ryccardo

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Yes but it will be somewhat wasted (XT-IDE the card is designed for 8-bit slots after all), the controller is usually not the cause of size limits (especially if it's a traditional non-accelerated not-really-controller) and you can get better value by using only the XTIDE Universal Bios using a ROM card...

...and you don't have to buy anything to see if that's the case, you can just download (the option rom + its configurator), set it up for a standard IDE interface, download opromloader and combine it (copy /b or unix cat) with the configured rom, then write it directly (dd) to a floppy, and get the same result as a real ROM card except for convenience or free RAM 😀

Reply 19 of 21, by AlessandroB

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Ryccardo wrote on 2023-06-20, 15:35:

Yes but it will be somewhat wasted (XT-IDE the card is designed for 8-bit slots after all), the controller is usually not the cause of size limits (especially if it's a traditional non-accelerated not-really-controller) and you can get better value by using only the XTIDE Universal Bios using a ROM card...

...and you don't have to buy anything to see if that's the case, you can just download (the option rom + its configurator), set it up for a standard IDE interface, download opromloader and combine it (copy /b or unix cat) with the configured rom, then write it directly (dd) to a floppy, and get the same result as a real ROM card except for convenience or free RAM 😀

i'm not be able to do that, outcome my actual skill. so the easy can be an IDE controller for the 286/386? scsi controller for the 286/386?