help2002

It's UWAweek 30 (2nd semester, week 1)

help2002

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UWA week 34 (2nd semester, week 5) ↓

1st project teh data-bus (both)

5:23pm Thu 24th Aug, Christopher M.

"Asher Blechynden" <23*5*1*3@s*u*e*t*u*a*e*u*a*> wrote:

> the project states that only one program may use the data bus at one time, but doesn't clarify what actions equate to a use of the bus. do all calls to a device require the bus (but not RAM, so a program can be executing on the CPU while one and only one device is working)? also, dose loading a command into the CPU require "accessing RAM", and therefor also require the data bus?

The data-bus is used when a process requests some I/O (either way), and the use lasts from when that process acquires the data-bus until the transfer of data completes. While the data-bus is in use by one process, another process can be using the CPU. "Magically" our system does not mention RAM, so we're not accounting for time to access RAM. I'm trying to get some (many) concepts across, without complicating the project.