> ... was missed for years simply because no one had a PC with more than two hard disks.
Thats a hardware limit:
Early mainboards only had a single IDE / parallel ATA port. Each port has two pins for drive select, so you had a maximum of two addressable drives, the master and slave drive.
With a secondary ATA port you got another set of master/slave, pushing the limit to 4 drives.
That's where the "primary master" text comes from that showed up on the screen during booting.
You're jumping ahead a bit... early motherboards didn't have drive adapters at all, let alone IDE or PATA. And it wasn't really limited to two by the board and expansion slots nearly as much as the physical form factor and cost. "Full-height" 5.25" drives are double the height of what you think of for say a CD drive bay or later floppy drive bays. There were two in the XT/AT cases that were common. Hard drives went from full-height 5.25 to 3.5" pretty quickly and there weren't many half height or otherwise short 5.25" hard drives. There was a "big foot" drive that sucked, that I recall though.
Most people I knew with computers prior to 1992 or so either booted from floppy or had less than 40mb hard drives. They were expensive. By the time I got more into the hardware (1994 or so), dual IDE was common (4 devices) and PATA transition was pretty seemless. The only reason I'm even aware of the difference is I worked at iomega for a while, and the IDE zip drive was IDE and not PATA.
Around 2001, I had a motherboard with dual PATA and another PATA that was via onboard raid controller. I had 4hdds, a cd burner and an ide zip at that time. The drives I had first used were the first IBM Deskstar drives... fast, but died very prematurely... the second died before I could RMA the first. I had switched from OS/2 to Windows 2000 (not ME) around that time. Then came SATA, and no more rounding pata cables.
When we got our first (10M) hard drive for our IBM PC (the original IBM PC), we had to buy a second case for it; because the power supply in the first one couldn't power it. On the positive side, it meant we had somewhere to put the TV we were using as a graphics monitor (since the main monitor was a green monochrome monitor).
Wow it's been a minute since someone talked about the IBM "deathstar" drives. I remember building a PC and dumping my last money into a hard drive - ended up with a maxtor but envied the benchmarks of those IBMs. They later started failing in droves.
Yeah... it was crazy fast for the time, but when you lose, you lose. Not nearly as bad as the 3TB Seagate enterprise drives I had in an 8 drive array... 6 of the 8 failed days after the relatively short warranty. I've had exceedingly good luck with all the ssd/nvme drives I've used though.
Built my first pc in 1987. RLL/MFM were the drive choices. I had a 32 MB had entering college and it was cheaper than 640 KB of DRAM DIPs. I upgraded to a 100 MB ide in 1992 for ~$220 US. But I Was booting from HDD from day 1 in 1987.
Similarly, it always bothered me a little that the floppy disk interface was designed for 4 drives, but the PC standard came up with the clever hack of putting the twist in the cable, so they didn't need to adjust drive jumpers, which also reduced it to 2 drives.
On the TRS-80, they just ordered all the drives jumped with all 4 positions, then pulled out the other 3 unused pins in the connector on the cable.
The twist as a "cute" solution that made it mostly plug-and-play; the biggest upgrade on some of those older machines was adding a second floppy, and the twist made it simple and foolproof.
... like in the PC AT, PC XT[1] or the Compaq DeskPro 386[2] that the article discusses didn't have those ports at all.
Those were instead on ISA expansion cards, just like the floppy controller that would often share a card with the UART controller for the serial interface.
IDE was just coming in (in the UK) in 1990. The acronym got updated to "AT Attachment" because "Integrated Drive Electronics" was generic, and it wasn't as if the older drives had no electronics on them. Much later when SATA showed up, the name evolved again as ATA became known as Parallel ATA to distinguish the two.
Before that, when you installed a hard disk you had to go into the BIOS to specify the geometry of the drive. 46 types were already defined, to match individual drives on the market. "Type 47" allowed -- required -- manually specifying the drive geometry in terms of cylinders, heads and sectors. So for a short while some traditional MFM or RLL drives would be informally classed as Type 47 because their geometry and capacity differed from earlier drives.
Yes, the earliest mainboards I know of with on-board I/O including ATA is around Socket 5, the first mainstream Pentium boards. Some slightly older Socket 4 boards (circa 1994) have on-board I/O, but they weren't as common.
My 486 and earlier systems have all I/O provided by ISA cards, other than the 5-pin DIN keyboard port which was standard since the original PC.
I remember my dad's Dell 486P/33 from 1991 had integrated IDE, but that was a fairly high-end machine at the time (the forerunner of their "Precision" workstation range).
Wow! Very impressive board, I had no idea. It's kinda cool how we can directly see some of the chips that would be on the SuperIO card but directly on the mainboard. Thanks for sharing.
White box systems didn't really acquire onboard I/O til the late 486/early 586 era, but it was pretty common on name-brand systems to integrate IDE/floppy/serial/parallel and usually video.
Thats a hardware limit:
Early mainboards only had a single IDE / parallel ATA port. Each port has two pins for drive select, so you had a maximum of two addressable drives, the master and slave drive.
With a secondary ATA port you got another set of master/slave, pushing the limit to 4 drives.
That's where the "primary master" text comes from that showed up on the screen during booting.