Thursday, June 18, 2015

How Crash Bandicoot Was Fit Into 2MB of RAM

Dave Baggett (via John Carmack):

The PS1 had 2MB of RAM, and we had to do crazy things to get the game to fit. We had levels with over 10MB of data in them, and this had to be paged in and out dynamically, without any “hitches”—loading lags where the frame rate would drop below 30 Hz.

It mainly worked because Andy wrote an incredible paging system that would swap in and out 64K data pages as Crash traversed the level. This was a “full stack” tour de force, in that it ran the gamut from high-level memory management to opcode-level DMA coding. Andy even controlled the physical layout of bytes on the CD-ROM disk so that—even at 300KB/sec—the PS1 could load the data for each piece of a given level by the time Crash ended up there.

I wrote the packer tool that took the resources—sounds, art, lisp control code for critters, etc.—and packed them into 64K pages for Andy’s system.

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