[A83] Re: Problems with Virtual TI [OT]
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[A83] Re: Problems with Virtual TI [OT]
Sorry, but that's entirely incorrect. The SysRq key has been on keyboards
since the 84 key keyboard with the original IBM PC. It's a normal key like
any other. The BIOS doesn't put the key into the keyboard buffer. Since
modern operating systems don't use the BIOS to read keys, that aspect is
pretty irrelevant. You can read the key as a scan code like every other
key.
The 286 had a protected mode that allowed it to access up to 16 megs of
memory, but it has nothing to do with the SysRq key. Entering protected
mode on the 286 involves enabling A20 on the address bus, building the GDT,
and enabling protected mode on the CPU machine status word, along with some
other things necessary if you want to be able to leave it.
> The SysReq key was brought in under the 286 for a System Request. What it
> does it move the machine from being a normal 16-bit machine with a memory
> cap of 640K to a Protected Mode machine with access to more the 1Mb of
> memory capability. Different OS's use it for different things now, such
as
> switching to a 'fix' mode. On many keyboards, it has become a CTRL
> function of the printscreen key, as screenshoting is more important to
some
> people than keeping their machine up without restarting. The SysReq key
> has become like Scroll Lock and Pause: Only people who really know what
> they are doing use them. Pause, for example, can help debug your startup
> under DOS or Windows by stopping the load sequence until you press Enter.
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