Well, I've been having such a blast lately with this little big machine!
So I've been testing how far can I take it, and in that process I had almost filled its hard disk of about 500 MB. I had less than 17MB of free space left!
When
I first disassembled the laptop about a month ago, the hard disk looked like a proprietary black box, but then I didn't think twice about it as I had many more immediate things to try in the machine. However, now that I was so tight in free space, I had no choice but to revisit the hard disk issue.
And then I remembered I had somewhere an old IDE 2.5" disk, from an old Pentium-II laptop whose original hard disk I upgraded a long time ago (I think that was around the year 2001, pheww!). So I looked for it, and I found it - that new found disk happens to be a very nice IBM-branded "Travelstar" 4.8GB laptop hard disk (quite fitting for a ThinkPad, me thinks) with the "astonishing" speed of 4200 rpm:
So I reach for my handy dandy retrocomputing tool case (bought for 6 euros at some German Lidl store in Madrid), and proceed to crack open the original hard disk enclosure.
That's how it looked like and what was inside of it:
A heavy IBM-branded made-in-the-UK 2.5" IDE hard disk, with a "strange" geometry:
1047 cylinders, 16 heads, and 63 sectors per track. So, if that disk works in this laptop being 1047 cylinders (and not 1024 which is usually the maximum number of supported cylinders in 486-era BIOSes), then the laptop's BIOS must support "Large Addressing" of hard disks up to 8GB, right? Looks promising...
So I remove the old hard disk, install the "new" one in the black enclosure, and connect the enclosure to the Thinkpad 755CE, which I eagerly proceed to power on... only to be welcomed with this sad, sad, sad screen:
And then, for good measure, with this other:
Oh, DAMN! Quite frustrating, if I may say so. :eh:
At this point comes the usual rigmarole every tinkerer loves to hate: check and double check the conections and cables, try and double try the process of assembly, explore the BIOS options like a mad man with eyes wide open, the whole this-is-not-working-but-damn-if-I-give-up experience we all quite know...
But nothing,
error 174 it is, and it doesn't want to go away.
Fine, so I decide to go to have something for dinner, just to let the problem cook itself a little... When I come back, I hit Google real hard. And
there it is, the elusive answer, buried in a mailing list post dated 1999, waiting to be read by the afflicted Thinkpad owner. :D
>BUT
>2. the drive select was changed from the time of your original HDD.. reversed, in fact..
>3. depending on the HDD shell you're using, it is most likely telling the machine that the drive is a
>slave, thus the machine does not see the drive and you get the 174 error..
So, it seems that in the interim between 1995, when this Thinkpad was made, and 1999, when that was posted on a mailing list about the same problem I now have, the "industry standard" for setting the master/slave configuration in laptops' hard disks had changed. According to that post, my "new" hard disk is getting configured as "slave" by the Thinkpad's hard disk caddy assembly, and therefore the BIOS does not see it, or sees it as wrongly connected, therefore: ERROR 174.
As the caddy hard disk assembly attaches tightly to the hard disk's IDE conector, there is no room to set a jumper to change that suspected behaviour. So, determined as I was to scape the infamous ERROR 174, I however reluctantly proceeded to bend the pin which helps sense the master/slave configuration, thusly:
And then I attach the connector assembly, with the bent pin sticking out:
Alas, it worked! No more errors, straight boot with a floppy, FDISK, FORMAT, Ghost back the C: partition, and I'm in business again, with plenty of room to try even more retro software and more retro games.
PS: Yeah, it's a minuscule hack, I know, but a great victory for me all the same! Yeay!