Restoring YC's Xerox Alto day 8: it boots
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Re: Restoring YC's Xerox Alto day 8: it boots
#2[deleted]
Re: Restoring YC's Xerox Alto day 8: it boots
#3As is said every time this blog updates: This is very interesting stuff and I enjoy reading about the progress.
I can't imagine the excitement these folks felt when the machine finally booted up. All of their skilled trouble shooting and hard work were spot on.
I can't wait to read more.
Re: Restoring YC's Xerox Alto day 8: it boots
#4I love it that its finally booting. I wonder if they've considered taking all the probes off, and booting without debugging hardware attached ..
Re: Restoring YC's Xerox Alto day 8: it boots
#5I love it that its finally booting. I wonder if they've considered taking all the probes off, and booting without debugging hardware attached ..
We'll leave the probes on until we're done debugging since it's pretty tedious to reinstall them. Is there any particular reason you suggest booting without the probes?
Re: Restoring YC's Xerox Alto day 8: it boots
#6This is an amazing milestone! I have to ask, why did we need a separate boot disk sent over instead of flashing the previous disk with the contents of a boot disk? I suppose swapping out parts is an expected part of restoration though.
Re: Restoring YC's Xerox Alto day 8: it boots
#7I love it that its finally booting. I wonder if they've considered taking all the probes off, and booting without debugging hardware attached ..
We'll leave the probes on until we're done debugging since it's pretty tedious to reinstall them. Is there any particular reason you suggest booting without the probes?
Probably out of fear that the signals might deteriorate with probes attached.
But with a modern-ish logic-analyzer and the ancient original hardware (huge voltage swings, slow clock, very long busses), I doubt that the probes would make a discernible difference, would they?
Re: Restoring YC's Xerox Alto day 8: it boots
#8This is an amazing milestone! I have to ask, why did we need a separate boot disk sent over instead of flashing the previous disk with the contents of a boot disk? I suppose swapping out parts is an expected part of restoration though.
Interesting use of the word flash here. It's a magnetic disk though, no flash chips, so you would just say write.
I imagine the issue was a lack of working drives, and Alto systems to run them.
Re: Restoring YC's Xerox Alto day 8: it boots
#9This is an amazing milestone! I have to ask, why did we need a separate boot disk sent over instead of flashing the previous disk with the contents of a boot disk? I suppose swapping out parts is an expected part of restoration though.
They don't currently have any way of writing to the disk except using the Alto itself, which would require booting it first. Once they get it working they should be able to create their own boot disk.
Re: Restoring YC's Xerox Alto day 8: it boots
#10This is an amazing milestone! I have to ask, why did we need a separate boot disk sent over instead of flashing the previous disk with the contents of a boot disk? I suppose swapping out parts is an expected part of restoration though.
To "flash" the previous disk (terribly amusing choice of anachronistic terms there) you need a working disk drive to drive the disk with. (You also need a disk controller, but you could probably cobble one together out of an Arduino and some TTL shift registers or something. Surely Ken could.) It turned out that their disk drive wasn't working reliably, so that would have been tricky.