[TUHS] UNIX on S/370
dave at horsfall.org
Thu Nov 30 08:42:51 AEST 2017
On Mon, 20 Nov 2017, Larry McVoy wrote:
> So tape I can see being more weird, but isn't raw disk just "don't put
> it in buffer cache"?
DMA too, hence the process is locked in core. I think the read/write had
to be a multiple of 512 bytes as well (I lost my Edition 6 manuals along
with my treasured -- and original! -- Lions books in a house move).
> From what I've been able to gather early tape in Unix was dicey,
> something about the driver doing seek. Was there more to it than that?
IIRC, the driver kept track of the current block under the head, and
issued forward/backward skips accordingly; I have no idea whether SimH
gets that right (as opposed to doing a random seek).
(It bloody well worked, Mr Minnich, OK?)
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."
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