Mike's PCjr Page

Franko wrote:

Gremlin5 wrote:Is there a reason you are interested in a DOM over say a CF card with an adapter?

I was focusing on DOMs because I got the sense they were spoken of more highly in most of the threads I've looked at here. Not entirely sure why -- maybe lifetime write cycles? Or which are more likely to work with the jrIDE?

I'd be interested in giving a CF card and adapter a try at this point. But I'd really want to make sure that what I'm buying is known to work with the jrIDE. Do you have any links for the adapter you use? Given a choice I'd probably buy from Amazon if prices aren't too far off, because of their fast shipping. But eBay or elsewhere would be ok too.

It would also be great to know specifically which Sandisk CF card(s) work for you. I have drawers full of SD cards, but only one or two CF cards, and these were from back in the days when a 2 MB card was considered big.

Well I forgot to add the setups I'm using are on PII 266 and Athlon 1200 machines that are native ide hdd machines. I dont have a jrIDE so I'm not sure if it would work or not, I have no way of testing.

I dont mean to sound cheap as I really really want a jrIDE I'm still try to decide about adding a $100 addon to a JR I got for $30.

The adapters I have added to my machines are from Monoprice and work great and for my windows 98 drives. I use the 16 gig CF cards from Sandisk for win 98 and win 2k but for my dos 3.3 and 6.22 drives I just use the cheap generic chinese 2 gig CF from memorypartner ltd. I use the same dos CF in my all my machines including my 2 IBM XTs, its only my JR that doesnt have any kinda setup for CF to ide. My XTs share a XT-CF Eco-Lite that I move from machine to machine as I never use both of them at the same time.

This is what I use but this should basically be the same except without the bracket and need for a cable. BTW I dont vouch for any of these companies I just know what has worked for me.



Edit: I forgot you asked.. This is the sandisk CF I use.. notice it does say refurb on cards (how do you even refurb a CF card?) and this is the cheap generic 2 gig CF card I use for dos... they take awhile to get here so.

Thanks. The CF card adapter is cheap and ships from about 15 miles away from me, so it's easy to try. Should be able to get a CF card as well.

Yours is not the 1st thread on this: viewtopic.php?f=1&t=737

Odd I knew I read that thread before and forgot about it and yet its still on the 1st page of the PCjr Hardware and I didnt see it until now.

I think that all Disk On Modules support CHS addressing. I would be surprised if they did not support LBA addressing.

If the Disk On Module is not being identified properly by the BIOS then it could be a cabling or a timing problem. Getting the identification string is a fairly basic operation; if that doesn't work then nothing else will. In your problem report you didn't show the BIOS identifying the Disk On Module; you should have had a human readable string there.

Brutman wrote:In your problem report you didn't show the BIOS identifying the Disk On Module; you should have had a human readable string there.

Here is everything that appears on the screen as I power up my 128K PCjr with parallel port sidecar, 3.5" backpack drive, MS-DOS 3.21 boot floppy in A:, and jrIDE board with attached Hyperdisk 16GB DOM (model # DMV340S2I-016G-M013-B2):

PCjr irIDE BIOS version 2012-11-12 (http://www.brutman.com/PCjr)
Based on XT-IDE BIOS v0.11 (http://vintage-computer.com)

Base memory: 112 Total memory: 736

Drive 0:
Error! This drive is too old to support LBA access.

Drive 1:
Error! This drive is too old to support LBA access.


Press [ESC] for boot menu...
BACKPACK.SYS: Copyright 1994, Micro Solutions Inc., DeKalb IL.

The following BACKPACK drive is available:
Drive C: - 3.5 inch 1.4MB


BACKPACK.SYS is using 13.25K of memory


A>echo off
Microsoft(R) MS-DOS(R) Version 3.21
echo (C)Copyright Microsoft Corp 1981-1987
(C)Copyright Microsoft Corp 1981-1987

I'm still interested in why it refers to two drives (a Drive 0 and a Drive 1).

Because the XT-IDE Universal BIOS supports two drives, so it checks for two drives.

I'm still interested in why it refers to two drives (a Drive 0 and a Drive 1).

When the BIOS can't communicate withe the hardware, all bets are off. This is why it is reporting the DOM doesn't support LBA (it does; all DOMs do) and why it thinks there are two drives when there is only one. The BIOS assumes things are working, and when things don't, it'll go sideways pretty quick and you get lots of weird messages.

Thanks for the explanations.

I've now had the chance to try several storage devices with the jrIDE board. The results:

Devices that are recognized
- Hyperdisk 512MB DOM
- Lexar 2GB CF card (thanks to Gremlin5 for recommending this adapter: https://www.ebay.com/itm/Standard-Compa ... 3908353712)

Devices that result in "Too old to support LBA access" error
- Hyperdisk 16GB DOM
- Sandisk Ultra 16GB CF card

Is the issue with the size, i.e. the ones that don't work are larger than 8GB? (Not that I need one larger than 8GB, if even that.) The two Hyperdisk DOMS have similar model numbers, appear to be of the same vintage/product line, and the only obvious difference is their storage size.

Size of DOM shouldn't be a factor in the BIOS being able to detect and work with it.(1) Size only matters to the OS.
It is very odd that the same manufacturer can produce DOMs that work and ones that don't- typically it's all or nothing as much of the interface is identical between products, but we'd need to closely examine the PCB and the reported firmware revision to really nail down why.

1 - The only time the BIOS looks at the size of the drive is to set up Extended INT 13h support, but this would be _after_ drive identification stage, and that is where the "too old to support LBA" message is coming into play. Since we're only using DOS on our PCjr, there is no need to have Extended Int 13h enabled. Mike may have removed support for that.

I have been using CF to ide adapters but been meaning to pick up a SD to ide adapter as they have dropped in price and SD cards are so much cheaper than CF cards and can get them about anywhere locally.

I even thought about Sata to ide adapter as 120 gig SSD are getting really cheap but as most of my really old machines use OS that wouldnt make that size practical and any of my other machines that could use that size storage already have some sort of Sata controller on the motherboard already.