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Compaq Contura Aero 4/25 486 laptop (1994).
Cost me £12, it needs repairs to the screen bracket & a clean. Also I have no idea if it will work, additionally it has no PCMCIA floppy drive. BIOS info stored on a hidden partition on the HDD, no floppy = problems
@Gammitin@mastodon.socialWow, the 171MB Seagate HDD is still working and it boots into MS-DOS 5.0. There's some 'interesting' names batch files on here 
Checking out the Compaq setup, that's actually a hidden partition on the hard drive. Honestly, this is a reason why I don't rate Compaq at all, what the heck were they even thinking!? Don't be fancy, we don't need a mouse and cut down Windows 3.1 just give us a BIOS on chip. 
Take apart time, I really want to try to come up with a HDD solution as this drive won't last forever, also replace the cmos battery.
I've literally spent hours tonight trying to set up a CF card using VMWare and ghosting images etc. I've found out that actually none of my CF cards are compatible, as I used a small IDE HDD and it worked straight away.
It boots into the setup partition, but the HDD is 4GB, 512mb is the max for this system, so no go. I need to pick up some more CF cards and do some experimenting.
It's 3:00AM here, I have insomnia, so decided to do some more messing around. So this DIAG partition / boot sector malarkey got me thinking 
DRIVE OVERLAY SOFTWARE!!!!
Yes, that's 2.1GB and it boots, yassss!
EZ-Drive was the winner, On-track didn't work how I wanted it too, the good thing about EZ is the partitions are mountable, so EZ file transfers too! 
I'll try to install Win95 tomorrow, it seems to be a 486 week this week!
I've been doing Christmas decorating all day, finally got a bit of time, fingers crossed this actually works and boots, 2GB FAT16 partition.
Windows 95 was a bit of an experiment, it crapped out, not surprising as it only 4mb or RAM. I have however now devised an 'easy' method for installing an OS on these Compaq systems with a DIAG partition. If you have no floppy drive and no options, you do now. 2.1GB MS-DOS 6.22:
Anyone who knows me, knows that my favourite thing to do, is to stick Dupont wires into stuff. Well I've done some digging on this low-force helix (LFH 60Pin) connector on this laptop. It's an expansion port and I think I've figured out how to get a VGA signal out of it!
Compaq Contura Aero update:
The VGA out didn't work, but not really sure why I need it anyway 
I fixed the snapped hinge, also greased them up, as it was stuck solid (probably why it snapped)
It has always blown my mind how Pinball Fantasies is able to play music and sound effects through a PC speaker (no sound card).
I've been meaning to make an ESP SLIP router for a while, so today's the day!
This allows computers to access network and internet via the serial port, works for many platforms, including MS-DOS. Very simple to make, this is all you need:
ESP8266 (Wemos D1 is fine) + RS232 to TTL
@Gammitin interesting .BAT files on top of the screen 
@Gammitin I wonder if it's a LBA vs CHS compatibility issue… the modern CF cards using LBA and the BIOS on this machine requiring CHS addressing.
I had one Advantech industrial PC that booted from CF cards… and had a lot of head scratching figuring out why it wouldn't boot until I realised it was set in BIOS for CHS. Switch it to LBA and hey presto. Debian Bullseye is running on it now and it's a happy little router VPN at my workplace.
@stuartl that's what it will be, it's an old bios, only supports up to 512MB drives. I'll try to get some industrial ones.
@Gammitin Did you just replace the LCD… it was monochrome in https://mastodon.social/@Gammitin/113608426164715510 but colour here?
@stuartl just the lighting, I was sitting in the dark at 3am
@Gammitin Interesting, because I _have_ run Windows 95 on 4MB RAM… a 386 SX/25.
I'll admit it doesn't exactly run well… like a 3-legged dog with arthritis… but it does run.
I wonder what killed it on this occasion.
@Gammitin did those compaq have an upgrade to 8 or is it possible? iirc, 95-96 i had a monochrome 486dx33 generic laptop with 4 and it was just under the so-called reqs at the time so i wanted to run it but it wouldn’t install completely or had some other error, universal win95 hardware compatibility was still shaky in those early years too sadly
@dole expandable to 20 MB apparently
@Gammitin Get an 8 gigger to work and I'll be impressed. 
@Gammitin reminds me of the mod trackers back in the day that could do the same, play music through the pc speaker that wasn't just bleeps and blips.
@Gammitin It's a marvel. Playing a wav over the PC speaker is actually not that hard (just do a OUT to a specific port at the correct rate, after reducing the wav to 1bit)... the hard part is doing other useful things while that time sensitive code was running on an operating system that wasn't even remotely multithreaded. Like, say, an entire pinball game. That is outstanding.
@Gammitin The reason I own an Amiga 500.
@Gammitin All sound is just a bunch of sine waves stacked on top of each other, and a square wave is just a really awkward sine wave. 
@Gammitin dx(1), 25mhz, a masochist
@Gammitin I've struck that too… my sister's later Pentium still ran a cut-down Windows 3.x-based "BIOS".
Made me wonder what would happen if the disk failed how does one recover the machine?
That said, modern UEFI probably has a "bigger" footprint than this does.
@Gammitin Could you perhaps image that hidden Compaq Aero POST setup partition and compare it to the one in https://archive.org/details/contura-aero-system-image-back-up to check whether yours differs? Maybe then save it to bitsavers and/or archive.org?
@Gammitin@mastodon.social Looks a little stale, maybe time to just hard-boil a new one?
@Gammitin I knew I was forgetting to do something. Thanks!
@Gammitin Absolutely! It’s important to clean your balls so they don’t feel grotty when you run your fingers over them.
and seat them properly in the ball ring @Gammitin
@Gammitin seeing this post in my feed reminded me that I need to boot up my old 3.1 desktop and XP pc when I go home for the holidays.
@skylark13 it just says in capital letters: "F£#@ YOU TOO!"
@Gammitin hahaha that's awesome!
@Gammitin You can't leave us hanging like that that, what were they?