[XCSSA] updating a kernel without rebooting

[xcssa@xcssa.org]

On Aug 18, 2006, at 2:18 PM, xcssa-admin@xcssa.org wrote:

> On Friday 18 August 2006 12:36 pm, xcssa-admin@xcssa.org wrote:
>> And yes, I do know both OS/9 and CP/M. I ran OS/9 Level I on a TRS-80
>> Color Computer (the only notable thing I did was write a console
>> driver using the 6K bitmap display mode),
>
> TRS-80 CoCo-II was my first machine..  I could never afford a  
> floppy drive
> though so wasn't able to really do OS/9 (plus I think you needed  
> the CoCo-III
> for that.

That was only to run OS/9 Level II, which supported paged memory.

>> and I worked with CP/M on a
>> TRS-80 Model II back in the mid-'80s that had a 5MB hard disk... with
>> four partitions!
>
> My first computing experience was on the TRS-80 Model-I.  Only 4kB  
> of RAM bout
> our school could afford a DUAL floppy drive!  Of course if you  
> powered off
> the system with a disc in the drive the flux collapse from the  
> biased R/W
> reads would "zap" you floppy and cause corruption -- causing you to  
> lose the
> blocky space invaders game that you just spent four hours typing in  
> by hand
> and debugging.

The disk controller required 16K minimum, because TRSDOS itself took  
up more than 4K just to load.  Actually, Level II BASIC required 16K,  
so there was no such thing as a 4K L2 system.

But if you were using a 16K machine, you would indeed have about 4K  
of RAM left after loading Disk Basic.  And I do remember having to  
open the drive doors before turning power off.  You would even see  
all the select LEDs on all drives flash when that happened.

  - Bruce -