Need info on 16-bit DMA for AT

[Scott "The Pseudo-Hacker" Neugroschl]

In article <13366 at steinmetz.ge.com> davidsen at crdos1.UUCP (bill davidsen) writes:
]In article <1751 at csuna.csun.edu> abcscnge at csuna.csun.edu (Scott Neugroschl) writes:
]
]| Any Xenix users out there want to talk about losing RS-232 interrupts during
]| disk access because of this?
]
]  I do. I run an original AT with xenix 2.1.3, with input coming in at
]2400, 9600, and via ethernet. I have never seen any indication of lost
]interrupts. I also run a 386 at home, 2.3.1, with two 2400 lines and a
]9600, all on dumb ports. No problem.
]
]  Where have you seen this?

2.2.1, most notably during getty.  Also during ASCII uploads (9600/7/1/odd)...
Loses console and serial interrupts during disk access... Maybe I'm assuming
the wrong reason, but I've had friends who wrote device drivers tell me that
the disk is run from the CPU rather than DMA, and with interrupts disabled...

Anyone familiar with Xenix Sys V 2.X internals know anything?

P.S.  This is on a True Blue AT339 (8MHz, 1MB (counting the genuine Intel
Above Board), ST-4038 HD.


-- 
Scott "The Pseudo-Hacker" Neugroschl
UUCP:  ...!sm.unisys.com!csun!csuna.csun.edu!abcscnge
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