Could it be related to the fact that it is a 2GB SD card and I believe IDE controllers of that day could only address something like 500MB? Should I consider trying to partition the SD card into a 500MB partition? Eugene From: Richard Cini <rich.cini at verizon.net> Sent: Friday, June 26, 2020 6:08 PM To: W2HX <w2hx at w2hx.com>; General Discussion: On-Topic Posts <cctech at classiccmp.org> Subject: Re: IDE-SD adapter question Off hand, I wonder if the 486 doesn't support logical block addressing in the BIOS (or its not enabled). Modern machines (and those of a Windows 95 vintage) do not use CHS addressing (cylinder, head, sector) any longer. SD cards usually don't return Sector errors because of the dynamic remapping the firmware does. Rich Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: cctech <cctech-bounces at classiccmp.org<mailto:cctech-bounces at classiccmp.org>> on behalf of W2HX via cctech <cctech at classiccmp.org<mailto:cctech at classiccmp.org>> Sent: Friday, June 26, 2020 5:39:57 PM To: cctech at classiccmp.org<mailto:cctech at classiccmp.org> <cctech at classiccmp.org<mailto:cctech at classiccmp.org>> Subject: IDE-SD adapter question Hi all, Thanks for previous help on this project. I am working on an old 486 computer and I have replaced a 40 pin IDE hard drive with this SD adapter... https://www.amazon.com/gp/product/B07G29TZPS/ref=ppx_yo_dt_b_asin_title_o01… In general it seems to mostly be working. I can see a directory listing of several thousands files located on a 2GB SD card from yesteryear. The SD card was new when I installed it (has been in my possession for years). However, I do get errors "sector not found" and if I A)bort I get INT 24 error. I am trying to get windows 95 installed and this is certainly preventing that. In the BIOS settings I have the hard drive set as "USER" and these parameters: CY:[1024] HD:[16] ST:[63] LZ:[1024] WP:[0] These were the parameters in use while I was still using the actual hard drive. Question 1: Now that I am using an SD card instead of an IDE drive, what, if anything, should I be doing with these BIOS parameters? Question 2: The BIOS has an option to format the hard drive. Should I format the SD card using this facility? I did not explicitly put a filesystem on that SD card. I placed it in a windows 7 machine, it was recognized, and I began copying files to it. I then place the SD card into the 486 machine where I saw the sector not found errors. Any advice how to proceed? Thanks Eugene

On Sat, 27 Jun 2020 at 02:30, W2HX via cctech <cctech at classiccmp.org> wrote: It could well be, yes. Won't help. It's at a level underneath partitioning. A disk manager might help. Here's a legit freeware download: https://www.philscomputerlab.com/ontrack-disk-manager.html This is: https://en.wikipedia.org/wiki/Disk_Manager -- Liam Proven ? Profile: https://about.me/liamproven Email: lproven at cix.co.uk ? gMail/gTalk/gHangouts: lproven at gmail.com Twitter/Facebook/LinkedIn/Flickr: lproven ? Skype: liamproven UK: +44 7939-087884 ? ?R (+ WhatsApp/Telegram/Signal): +420 702 829 053

Peter and Maciej. Thank you very much for the input. I don't believe this BIOS supports anything other than CHS. At least I don't see a way to toggle between CHS and LBA. Is this what I should be looking for? An option to enable LBA mode? I am not opposed to going to CF, but I have no other computers that have a CF port, thus I have no way to move files onto this 486 computer. Is there anyway to add LBA mode to this machine? A new BIOS? A new ISA card? Or am I better off considering a new motherboard altogether? Maybe more of a project than I was hoping for... I guess a possible solution might be IDE-CF card for the 486 and maybe a corresponding USB-CF for my daily PC for file transfer? Eugene -----Original Message----- From: cctech <cctech-bounces at classiccmp.org> On Behalf Of Peter Corlett via cctech Sent: Friday, June 26, 2020 6:15 PM To: General Discussion: On-Topic Posts <cctech at classiccmp.org> Subject: Re: IDE-SD adapter question On Fri, Jun 26, 2020 at 09:39:57PM +0000, W2HX via cctech wrote: [...] The description of that adaptor says "Attention: Some of the mother board required to enable LBA mode and disable DMA transfer mode." This suggests to me that it does not support CHS addressing, and as the Engrish says, you need to use LBA mode instead. If your motherboard only supports CHS, you're likely to have a hard time getting many of these cheap adaptors to work with it. You might have better luck with Compact Flash, since the adaptors are passive and the CHS/LBA support (or lack thereof) is a function of the card, which is liable to be of better quality.

On Sat, 27 Jun 2020, W2HX via cctech wrote: IIRC some old PC BIOSes indeed had an option to switch between CHS and LBA, it's been a while. It might have been on a per-drive basis, at least with some implementations; as usually, for bug compatibility or whatever. This was all hairy stuff, now that you have reminded me. Using Linux did help a lot back then, the system was especially ambitious in its early days (it has fallen a bit into routine IMO over the years; it's no longer hobbyists trying to make their best and squeeze out as much as possible from the hardware), so all that was necessary was to put all the boot stuff onto a partition within the first 528MB, even with fake CHS parameters in the BIOS setup, and forget about all the PC BIOS limitations as the kernel handled all automagically, including geometry discovery and switching between CHS and LBA as necessary (IIRC there was an override too for the user to pass at kernel invocation in case the firmware of a given drive had a bug with one of the modes or whatever). CF to PATA adapters are readily available and can be used to wire CF media to any machine talking PATA. I have one of those adapters that actually supports both a master and a slave CF device, so you can plug two CF devices at a time, just as with original ATA devices on a flat ribbon cable (from StarTech; it may not be available new anymore and I have it at a remote location, but I can check the P/N when I'm back at it or perhaps track down the original invoice in my e-mail archives if that would really help you). Of course you can bridge such an adapter to SATA or USB or whatever, just as with a genuine ATA device, so you should be able to wire it to a modern machine pretty easily. But actual PATA adapters for PCIe used to be made too as I have a couple myself that I bought not so long ago so as not to be stuck with vintage hardware for data copying involving a PATA device, so tracking down one being sold shouldn't be a big deal yet. You might be able to track down an actual hard drive in the CF form factor too (branded Microdrive by IBM IIRC, a 1.8" device), though the choice was rather limited. I have one of those from Seagate at 2.5GB, extracted from a TomTom sat nav that I upgraded to solid-state CF of a larger size several years ago. I used that dual CF adapter I mentioned above to copy data between the two storage devices. Those true hard drives ought to be pretty much compatible with anything, as they're ordinary magnetic devices, just smaller: /dev/hda: CompactFlash ATA device Model Number: ST625211CF Serial Number: [...] Firmware Revision: 3.04 Standards: Likely used: 6 Configuration: Logical max current cylinders 4845 4845 heads 16 16 sectors/track 63 63 -- CHS current addressable sectors: 4883760 LBA user addressable sectors: 4883760 Logical/Physical Sector size: 512 bytes device size with M = 1024*1024: 2384 MBytes device size with M = 1000*1000: 2500 MBytes (2 GB) cache/buffer size = 128 KBytes (type=DualPortCache) Capabilities: LBA, IORDY(cannot be disabled) bytes avail on r/w long: 4 Standby timer values: spec'd by Vendor R/W multiple sector transfer: Max = 16 Current = 16 Advanced power management level: disabled Recommended acoustic management value: 128, current value: 128 DMA: mdma0 mdma1 *mdma2 udma0 udma1 *udma2 (?) Cycle time: min=120ns recommended=120ns PIO: pio0 pio1 pio2 pio3 pio4 Cycle time: no flow control=120ns IORDY flow control=120ns Commands/features: Enabled Supported: * SMART feature set * Power Management feature set Write cache * Look-ahead * WRITE_BUFFER command * READ_BUFFER command * NOP cmd * CFA feature set Advanced Power Management feature set * Mandatory FLUSH_CACHE * CFA Power Level 1 (max 330mA) HW reset results: CBLID- below Vih Device num = 0 determined by CSEL Integrity word not set (found 0x0000, expected 0x1ca5) You might be able to chase one of those sophisticated cards that I mentioned, which obviously had their own expansion BIOS hooking up into the PC BIOS. I don't know though how common they are these days on the second-hand market. Some old hardware seems to be unobtainium, almost never if at all surfacing, while other is ubiquitous. I don't know why. I wouldn't bet on a PC BIOS upgrade for such a specialised machine. They were supposed to be used in their supported vendor-provided configuration, so what would be a functional firmware upgrade good for? A critical bug fix is another matter, but that would not add such a major feature as LBA support. Another possibility would be a SCSI host adapter. They have always come with their own expansion BIOS, so any limitations of the base machine's PC BIOS are not relevant. I reckon there have been SD to SCSI adapters available. As I noted above I think an IDE-CF adapter is probably the easiest option and you can use it both with your intended machine and with any other as well. No need for a separate USB-CF piece to transfer data unless you want that too, that is. HTH, Maciej

Eugene, It didn't strike me why you needed to use SD rather than CF. As my memory has certainly already faded to some extent in this area I did a little investigation, and with some reminders I came across I need to mention the requirement to make the CHS geometry recorded in the MBR partition table match one reported by the PC BIOS (as entered in the setup program) and the device itself. The ATA protocol provides for CHS geometry modification with one of the optional commands that the PC BIOS or other software may use for one reason or another, but the adapter may not necessarily support it, so one used with the PC BIOS of your intended device does need to match one used with the firmware. To make sure this doesn't get broken somewhere on the way you may want to start from scratch and erase the partition table on the SD card. I can't provide you advice other than with Linux as to how to do that, now that UEFI is in picture. Once that has been done you need to establish the CHS geometry the adapter will use with your SD card. You can use a detection program as I noted previously, however a 2GB unit is surely above the 528MB limit, so you can guess 1024/16/63 will be right as that is the maximum of the intersection of the ATA and PC BIOS CHS geometry limits and the adapter ought to handle it if it does the CHS stuff at all. So use that with your intended computer's PC BIOS setup. Then boot the machine from a floppy or another device, with the SD and the adapter wired, and use whatever tools the OS has to partition the SD. Install the MBR as required. E.g. with DOS this will be `fdisk /mbr', and the same command with no arguments to make the partition table. If you can use a Linux machine, then I can help setting up the SD card directly. I have come across: <https://www.vogons.org/viewtopic.php?t=60169>, where people report success with hardware as old as 80386, whose PC BIOS surely had no idea about LBA, and there haven't been that many ATA-SD adapter chip designs made, so chances are yours will work too with sufficient care, and the warning as to the use of LBA may have simply come from the difficulty to set up SD medium for CHS operation correctly. HTH, and good luck! Maciej