dukeofurl wrote on 2024-02-28, 15:11:

Is the CHS reliant on the particular ide adapter I'm using?

If I understand the situation correctly you have problem with your modern computer and vintage one deciding to map LBA and CHS differently for your CF card?

CHS translation is performed by BIOS, and internally by the CF card once again as obviously those dont have any heads 😀. CF card always does same thing so is not an issue. BIOS pickling different way will scatter data in unreadable way.
Re: 486Dx2 build driving me nuts!
BIOS translation modes: https://web.archive.org/web/20180719185154/ht … /bios/modes.htm

One thing you could try is write a script to fill your CF card with easily recognizable pattern. For example incrementing counter every 512 bytes. so 512 zeroes, 512 ones 512 twos etc etc. Then put the card back in vintage computer and read it sequentially to observe how the mapping changed.

Taking a break from the CF for a second and looking at the old hdds we used with this machine... and by golly, our master was 1.2GB in capacity. So much for the anxiety that the PC is only going to support 300mb storage or less. Its a possibility we were only able to use a portion of the drive... but I don't really remember that being the case. Will have to double check that these values can be inserted, thought there might have been a three digit limit on cylinders in the BIOS... (*edit, there was no three digit limit on cylinders in the bios, though ultimately there seems to be a limit for natively only seeing ~500MB on the storage device even if higher values are inserted)

Looking at the secondary slave drive, the maxtor, not sure what the numbers mean here. Does any of this translate to CHS? *Edit, this was a popular enough HDD that I found the CHS info online. 345MB, CHS = 790/15/57 in case anyone is googling this later.

Alright, managed to figure out a roundabout way to get CHS for the flash with the materials I have on hand... Modern PC>USB to IDE adapter>IDE to CF adapter>run HWinfo, which gave me the following:

256MB CF = 994/16/32
2GB CF = 4066/16/63

Will see if I have any luck with these values!

Update. I tried those CHS values I mentioned in the last post in the 386 bios, as well as 980/16/32 for the 256MB CF, but after running fdisk/mbr, formatting the CFs, and successfully copying files over to them, I have the same results as a few days ago: I can view files that I've put on the CFs, but if I try to run anything from the CF I get the "Not ready reading drive C" error, and on bootup, the PC won't boot from either CF and gives a fixed-disk controller error. Fdisk does identify the CFs as having a primary dos partition though...

...Actually, a slight difference from a few days ago is that I can read the CF on my modern PC and utilize and execute the files just fine on my modern PC using something like dosbox... so the files I've written to the CF on the 386 are recognizable and useable. It seems like I'm successfully writing to the CF on the 386, just not successfully reading from the CF on the 386/having the 386 BIOS consider its HDD settings to be correct.

Should I try to buy an industrial CF card that has a fixed-disk flag? My current consumer CF cards do not show up as fixed disks on a modern system, though on the 386, fdisk refers to them as fixed disks. Is it possible the 386 bios would have an issue with that? That's about the only thing left to try that I can think of.

Also, not entirely unexpected, but even if plugging in the full CHS for the 2GB CF, the 386 sees it as only a ~500MB HDD. Either way, I wouldn't really mind as long as I could read files from it 😀

Looks like you have an Ethernet card does it have the rom socket? If so an eeprom with xtbios will solve your cf card problems. I don’t use any of my 386 boards without it.
Another option is western digital disk overlay. I used it on a 386 laptop to boot a 1 gb cf card. Great for bios that force specific drive types.

dukeofurl wrote on 2024-02-29, 15:53:

Should I try to buy an industrial CF card that has a fixed-disk flag? My current consumer CF cards do not show up as fixed disks on a modern system, though on the 386, fdisk refers to them as fixed disks. Is it possible the 386 bios would have an issue with that? That's about the only thing left to try that I can think of.

I did have issues with some CF cards that identify as removable, non-magnetic media. This affected all mobos and BIOSes though and was tied to the particular IDE controller card I was using. I recommend Prime2C based cards if you have any, these I found to be most tolerant - though your particular machine might still have some BIOS quirks.

If you can get a good known CF card with fixed-disk magnetic media flags set then sure, go for it. Unless those are expensive in your area. Or try another IDE card if you have any on hand. That being said someone already recommended XTIDE BIOS extension for the network card ROM socket - if you have access to EPROM programmer to make such a ROM chip it might be a better solution. It does have its cons though, namely you loose some of the UMB area and your BIOS should have a ROM shadowing option enabled or you will suffer some performance penalty. Not to mention the network card must be present and it also uses some system resources and might conflict with other cards in future.

Pickle wrote on 2024-02-29, 17:56:

Looks like you have an Ethernet card does it have the rom socket? If so an eeprom with xtbios will solve your cf card problems. I don’t use any of my 386 boards without it.
Another option is western digital disk overlay. I used it on a 386 laptop to boot a 1 gb cf card. Great for bios that force specific drive types.

Hmm, I just removed it from the slot to look at it and this rom socket labeled boot rom looks promising.

Forgive my ignorance, what is xtbios? Is it possible to purchase an existing rom chip with it? I don't have an eeprom programmer.

Do you just plug in a rom chip into this card and it automatically replaces the existing bios with something that has more features?

Here’s a link to the project
https://www.xtideuniversalbios.org/

It does require a flash eeprom chip and a programmer (tl 866 ii). But if you had a programmed eeprom all you gave to is plug it in. Maybe you might have to change what address the network card loads it to but not likely.
It basically detects the ide controller and handles access to it bypassing the bios and whatever limits it has.

There are also stand alone cards with cf connectors. I think it’s also possible to program these directly over the Isa with its utility. I have one but I don’t recall which way I did it.

These cards are sold online and there might be just chip sellers. Depending on your location myself or someone could send you a chip.

The WD overlay does something similar but it’s all sw based. I’d give it a try (requires you can boot a floppy disk)

Wow xtide looks really interesting. I had no idea something like that existed.

I'd give WD overlay a shot but I'm unable to create my own 5.25 floppies right now, and that's what I'm limited to for getting files over to the 386.

I'm not readily seeing folks advertising chip provider services. If I could trouble you to program and send me a chip, I think that could significantly advance things. I'd be happy to cover any costs associated with that.

I checked and i have extra's. and checking mouser right about $5.50
https://www.mouser.com/ProductDetail/Microchi … bcAuBcLow%3D%3D
so we can work something out to get you one. Im trying to send you a PM.

Some other useful things you might not know about.
1. gotek floppy : emulates floppy drives using images on a usb stick. There is also open source firmware that expands what the drive supports.
2. if you have or can get the packet drive for that network card then you can use mtcp tools to enable dhcp and ftp in msdos: http://www.brutman.com/mTCP/
3. checkout phil computer lab for startup batch files: https://www.philscomputerlab.com/ms-dos-starter-pack.html
his benchmark set is also very useful: https://www.philscomputerlab.com/dos-benchmark-pack.html
4. if you add a soundcard consider those supported by unisound driver

Are those RCA jacks for supporting a light pen, i dont think its sound related?
Could be a cdrom card? Maybe thats what the empty 5.25 used to hold?

The other thing I dont think i saw mentioned and i cant see it from the pictures, but you need to figure how the clock battery is supplied. If its a varta barrel battery then you need to remove it before it leaks. Or if it has leaked then it has be neutralized and cleaned.

Pickle (and everyone else in this thread) thank you so much for your help and suggestions. It is making the journey here much less frustrating and more fun and interesting.

To satisfy any curiosity, the empty 5.25 bay was a 2x CD-ROM drive that I removed in the late 90s for another project. That drive connected to a mitsumi card, which is still in the PC, which is the card you see with the audio jacks. The battery is a rayovac battery and is off to the side in the case, not above the motherboard. It hasn't leaked yet and oddly, my recent bios settings are being kept so maybe it's being recharged now and still working on some level after decades? There is no sound card in the PC right now, but I used to run a gravis ultrasound in it and I have a modern day recreation of that sound card standing by id like to try installing after I can get CF booting going. it's decidedly low specs but this was my first gaming PC from about 1991-1996. I have a bunch of other things like the CRT monitor and joysticks I used with it 30 years ago and I'll be absolutely tickled if I can set up this relic and play stuff like Commander Keen and Wolfenstein 3D and other stuff of that era on it again after so long.

Nostalgia photo: playing the game Tyrian on it probably around 1996

Stardate 3/5/24:

Jumped the gun a little bit and bought a CD drive to fill the empty drive bay. Only after I bought it did I realize that I'm missing the mounting brackets/caddy to hold a drive! 😅 I must have taken it out when I took out the old CD drive 20+ years ago, that drive was eventually discarded, so it is likely the mounting hardware was discarded with it.

These kinds of items don't seem to turn up on places like eBay very often, and considering my make of PC is uncommon it's unlikely I'll get a 1x1 replacement. Is there a such thing as a universal drive caddy? (Haven't found one yet) Failing that, I'm thinking one of my next best options is buying a plastic caddy like for using a 3.5" accessory in a 5.25 bay, and tearing out pieces and drilling holes in it until I've got something that fits.

i had a similar problem on y 486 but i have a 3d printer. It would not be hard to reproduce the brackets attached to the floppy drive using a caliper to measure its dimensions.
I use tinkercad to model the object. Also Im pretty sure the pcb makers also do 3d print orders, might be an option for you. Otherwise its the same thing with the rom chip and getting someone to mail them to you.
I think it would be hard to find original brackets since things are so non standard this point in time.

Good news! I've been able to use the xtide bios to enable booting from my cf with no particular issues. I'm working on configuring my cyrix 486drx CPU now and realize I don't really know what a chunk of these options mean🤔. Any settings in here that might increase speed?

I’d grab Phil’s computer lab bench mark zip and run key 1 and key n to see what your perf is

Here's the benchmarks with no particular options tweaked for the 486drx

Then I started tweaking some stuff in an alternate cyrix program with the goal of trying to make sure the clock doubler and cache were enabled. I'm not sure whether what I tweaked was the right stuff, but I did get a performance boost, that was cool. But also several things stopped working. I ran the superscape benchmark and got a better number. The other benchmark crashed on startup and several games newly asked for extended memory and didn't run. None of this stuff is implemented in my startup yet, default slow settings each bootup as I try to figure out what the heck I'm doing. Wish I wasn't 7yo when my dad was configuring this machine in the 90s.

Check for a turbo switch I think it might off throwing the freq off in speedsys and turning off the cache.

Edit: You might not get much more out of this system. 10 fps in that test is around a low end 386 sx. I think when i ran my AMD 386DX 40 it was at 13 fps. So maybe highest 14 on this...
I think if things are normal you should see 50 mhz freq (double 25 mhz) in speedsys and then 1 kb L1 Cache in the graph. Im not sure if you motherboard has L2 now.
Is there any indication of the model motherboard, if we can find it on retroweb then the jumpers could be double checked as well.

Edit 2: Found another post with some speedsys numbers and looks like it doesnt show things correctly
Post your 386 Speedsys results here

key S shows another cpu detector, this might show the right speed
key T runs a cache checker and could validate the 1kb L1 is at least on.

Will do some further investigating tonight and tomorrow. The PC has no turbo switch. The motherboard says standard computer corporation in multiple places, I assumed it's their proprietary design but I suppose it could just be branding. I'll look for a serial no or so later, nothing is printed on the inside of the case in terms of a schematic or part no.

Certainly this will not be a blazing fast rig, but it was heartening to see the change in performance with superscape from initial results to tweaked settings results. It literally went from a slideshow to smooth animation with some of the complex scenes. Was likewise able to test Xargon, an early game designed for 386s with both settings. Default settings were much worse than I remembered with extensive slowdown. Tweaked settings were much better, very playable, maybe 90 percent what it should be. That's more in line with my memory.

Motherboard says "SN 901013" on it. I didn't get any relevant hits with a quick google search though.

Cache check didn't see the cache when run on default settings.

Over in this topic Register settings for various CPUs it is said that "The DLC/SXL chips have L1 cache enabled by default, however the whole 4 GB memory region is set as non-cacheable [by default], which doesn't allow for operation of the L1 internal cache. Use -i1 to inhibit region 1, thereby making this region cacheable." (with -i1 being an option in a particular cyrix configuration program). Utilizing this on my end gives me the result that cache check sees that the cache exists and games/benchmark programs get a noticeable speed boost. I'm basically going from 6FPS in superscape benchmark in default settings to ~12 FPS with the cache enabled.

CPUcheck in Phil's benchmarks gives speed as 49.7MHz. Cache check in Phil's benchmarks says 486 at 56.7MHz. HWinfo correctly identifies the processor name and speed as 50MHz.

With the cache enabled, shareware games run mostly as I remember. Apogee/ID/Epic stuff is mostly smooth and playable if not full speed, especially with detail settings turned low for those games that have customizable graphics options. I was very pleased to find out Jazz Jackrabbit and OMF 2097 are in the playable bucket with the cache enabled, I certainly remember playing them on the machine without thinking they were slow, even though I've seen in some places that people regard them as too demanding for 386s. A few more complicated games run slower than I remember (Mortal Kombat 2, Doom, Blakestone), but that might be rose colored glasses thinking they ever ran better than they do now. All in all, with the benchmark and info programs correctly identifying the clock speed and cache, I must be essentially at the optimum settings for this old 386, though I'd love to stumble on some esoteric setting that gives me a little more juice (for instance, the cyrix utilities have options for enabling/disabling barb, a20 and ken inputs and I don't really know what that means or if it would do anything on my machine, but might as well flip the switches and see if they do anything, right?)

Still have more plans for this machine on the software side, like installing Win 3.1, and getting the CD drive and a soundcard going.