Re: Advantage of XML based GUI? (was Re: Ada-inspired OS/Language)

[Kilgallen@SpamCop.net (Larry Kilgallen)]

In article <3d81400c.1027894993@news.cis.dfn.de>, nickroberts@blueyonder.co.uk (Nick Roberts) writes:
> On 12 Sep 2002 11:23:11 -0600, Kilgallen@SpamCop.net (Larry Kilgallen)
> strongly typed:

>>Existing device drivers that follow what model ?
> 
> Various and many. Maybe Linux. Maybe Windows. Probably a good plan would be
> to start with one that is relatively simple (but still works), and work
> towards the more sophisticated ones.

I believe such an approach would lead to a "tacked on" result such
as Windows NT, 2000, etc., with GUI from one heritage tacked onto an
operating system kernal from another.

>>Certainly that is fundamental to the design of the "native" device
>>driver system.  
> 
> A device driver may require: port I/O; memory mapped I/O; interrupt handler
> installation (and communication); communication with higher levels of
> software. What else? The design of AdaOS is very flexible. I suspect most
> DD environments would fit into AdaOS with little difficulty.

A Port and Class driver architecture, allowing in the simplest case
multiple drivers to share a single SCSI bus and in more complex cases
multiple ports to access the same device on a remote controller. For
a sanity check, I would suggest desk checking any design against
contemporary Fibre Channel hardware specifications to ensure that
IO to a specified disk can be handled over multiple paths.
 
>>Unless you design it from the start, for instance,
>>it would be difficult to deliver ASTs.
> 
> What is an 'AST' in this context, please?

Execution of code provided by the user, in user process context and
user processor mode when an IO request completes, independent of the
normal code flow of the user program.

======================

Of course I can only mention considerations I know about, I am sure
there are others with experience in other environments (IBM Parallel
sysplex, etc.) who should be consulted to understand high end device
driver environments.