Tube🌿Timei got a new Apple! 🧵
anyway, let's try and get this machine running. i have a funny feeling the video isn't going to work right...
sure enough, the machine chimes, but the video is blank. but i think i know what the problem is.
sure enough, there's no PRAM battery. these machines need that battery or you won't get video!
but where am i going to get a PRAM battery at this hour?
and we have working video! now for the most important question of the day: what version of Mac OS should i put on it?
i'm going to create a SCSI disk image for my SCSI2SD using BasiliskII and the instructions at https://www.savagetaylor.com/2019/12/19/how-ive-setup-the-scsi2sd-that-i-use-in-my-lc-475/
I was having trouble because I was putting the *volume* image into the SCSI2SD rather than the *disk* image. turns out partition tables are important lol
trying something else. unfortunately this didn't seem to work, I suspect the HFS partition needs to come before the ProDOS partitions.
well this explains why it was hanging. there's probably some setting on the SCSI2SD that's not exactly right.
turns out this hang was caused by the SCSI2SD firmware, which was uhh shamefully out of date. with the latest version it works and i can partition the drive!
it also turns out that MacOS wants to be the first data partition (i had the two ProDOS partitions first.) but it works now!
only had these poscaps hanging around. yes they're very fancy but they'll work.
wow, it totally worked! is it an Apple IIe or is it a Performa 475? why not both!
i figured out how to change the startup sound to "Quack" which makes me think of the Quapple (my Apple II ISA card that i cloned a while back)
time to check the capacitors on the motherboard. there really aren't that many chips on it! I was also able to remove it without any tools. just bend some tabs and it slides right out.
i found a tech manual. this is a very clean design. most things are tidied up into the two big custom chips, MEMCjr and Prime Time.
heh, they even put the bus sizing features in this chip. motorola removed that in the '040 (the '030 had it) and it caused innumerable problems for 68k computer designers.
William D. Jones@tubetime I wonder why a similar situation didn't cause problems in PC land when going from 8088 to 286 bus (and again from 286 to 386)? 8-bit ISA works (mostly) fine on newer machines. I wonder if this is a port-mapped I/O accommodation?
I remember hearing- emphasis on _only hearing_- the 286 has some _slight_ incompatibilities when talking to 8-bit devices with an I/O port at an odd address. But most cards in practice didn't run into this.
@cr1901 hmm, i don't know. intel was all about backwards compatibility, so probably the CPU handled it automatically.