Re: Ada 0Y plans for garbage collection?

["Nick Roberts" <nickroberts@blueyonder.co.uk>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
news:2q30nv4fain641rin9dia3onjr7ut01our@4ax.com...

[re booting and sleeping]
> Yep. Especially interesting it becomes with plug'n'play devices. You
> have, say a USB or PCMCIA device attached, before your Windoze
> hibernates. While it peacefully sleeps, you archly eject the hardware
> and then wake it up! The effect might be amazing, though predictable
> ...
> Of course in a truly memory-mapped OS, the present concept of
> hardware drives is out of place. One more reason for Ada OS?

I think the broad scheme I would like to adopt for AdaOS would be as
follows.

Each device driver, having at least once gone through a complete hardware
configuration procedure, would record the hardware configuration upon
shutdown. Upon the next reboot, the device driver would reinstate this
configuration, and would perform a quick check that the configuration still
accords with the detectable hardware (if this check failed, the full
configuration procedure would be activated).

With a bit of care, this technique should make it possible to fully shutdown
and then reboot very rapidly, but it would still be safe in the case of
intervening hardware changes (which would automatically cause
reconfiguration).

I intend to design the user application software for AdaOS so that it
(normally) remembers its important state in between the user logging off and
back on again. This is primarily to encourage users to log off whenever they
leave the workstation, but it also means that a user can log off, shutdown,
reboot, and log on, and all (or most) of their work (open windows) will be
reinstated as it was when the user logged off.

I don't know why operating systems (Windows, SunOS, and Linux in my direct
experience) are so slow at booting up, but I suspect it has a lot to do with
device drivers intialising themselves and their hardware. If this
initialisation can be either avoided (by the above tactics) or deferred (to
be done in the background after the boot procedure has got the system to a
usable stage), the user will perceive a fast boot process.

If the user can shutdown and reboot quickly (within a few seconds, I
suppose), and does not have to go through the rigmarole of closing a lot of
programs (windows) and then restarting them, I suspect the demand for a
'sleep mode' would be largely obviated.

If any OS is to be really secure, it must be basically reliable. I think
Dmitry has neatly illustrated the dangers of such fundamental complications
as sleep modes and other forms of partial shutdown. If a machine supports a
sleep mode, I think that's okay (especially as part of an overall power
management regime), but a full shutdown is better.

However, I'm open to debate!

--
Nick Roberts
Jabber: debater@charente.de [ICQ: 159718630]


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thanks.]