[JohnBooty]

Yeah, that's wild.

I imagine that on a physical vintage PC with a spinning rust hard drive (rather than in an emulator with storage presumably backed by an SSD) we'd be looking at a 1fps slideshow or less.

But, maybe I'm wrong! Maybe things would fit into the HDD's onboard cache and it would perform OK.

[deadlyllama]

Ha ha ha onboard anything

PCs of a sufficient vintage had so little logic on the HDD that you could swap out the MFM controller card in your PC for an RLL one and get 50% more storage. The modulation of the signal written to the disk was the job of the controller card, not the board on the HDD. Turn your 20MB HDD into a 30MB with a controller change and reformat? Mighty tempting.

[JohnBooty]

Hmmmmmm. I think they had some onboard cache around the time of DOOM? Now you got me interested....

This 4GB Western Digital AC-14300 with mfr date of 1995 seems to have 512KB of cache? Not sure if these specs are reliable though.

- https://stason.org/TULARC/pc/hard-drives-hdd/western-digital...

- https://www.ebay.com/itm/325794470911?hash=item4bdadd1bff:g:...

This 250MB Samsung from 1993 has 64KB of cache:

- https://www.directitsource.com/product-p/shd-3122a-ds2.htm

- https://www.youtube.com/watch?v=d-X2uYEx7tU

This WD Caviar 280MB from 1992 seems to have 8KB of cache.

- https://www.ebay.com/itm/154446527853

- https://www.priceblaze.com/WDAC280-WesternDigital-Hard-Drive

This 40MB Maxtor from 1990 has 32KB of cache.

- https://stason.org/TULARC/pc/hard-drives-hdd/maxtor/8051A-41...

So, I think any contemporary hard drive in those days would have some cache. Thanks for leading me down this nostalgic rabbit hole.

[jojobas]

On a modern emulated 286 the entire HDD image would be cached in RAM, and sometimes maybe in L2/L3 cache.