Re: Recommendations on a clock for an enhanced //e

[Michael Mahon <mahon@cup.hp.com>]

Michael,

mkelsey@spam.eecs.wsu.edu wrote:

> It looks like my ThunderClock Plus has lost the ability to store time.
> I had held onto it knowing that interrupts could be programmed and hoped
> at one point to begin tweaking with a multitasking kernel, but now all
> that fun has ended (sigh)

Before giving up on it, have you checked the batteries and their
terminals?  If it keeps time while power is on, then your problem
is limited to a very small number of components that supply battery
power when the computer is off (batteries, holder terminals, diode,..)

> What would be the best replacement for my ThunderClock?  I have several
> hard drives connected and I'd like to have a time/date stamp placed on
> files without having to enter the date manually.
> 
> I know AE and Thunderware made slot-based clocks and I also know of the
> "no-slot" clock, but I'm concerned about compatibility.
> 
> ProDOS (1.0.1) knew about the ThunderClock Plus and required no patching
> even with later versions (up to 2.0.3) aside from year calculations.
> I plan on keeping my //e beyond 2000, and I'm concerned about whether
> the AE flavors and the no-slot clock support beyond 2000.

Well, you will continue to have whatever years you patch into the
year table, so beyond 2000 is not a clock issue for the Thunderclock.

Your applications may have a problem with sorting dates, though.  ;-(

> So here are my questions:
> 
> [1] which clocks do not require patching with ProDOS 2.0.3?
> [2] does the no-slot clock require a patch for ProDOS 2.0.3?
> [3] which clocks support proper operation with accelerators?
> [4] which clocks allow for the enabling of interrupt timing?

_Everything_ requires patching, including the ThunderClock (for it's
year table).  BTW, the patching that the No-Slot Clock does is not
disk patching, but in-memory patching, and appears to be quite robust.

Most accelerators allow disabling acceleration on a per-slot basis,
so if you put the No-Slot under a slot ROM for a "don't accelerate"
card (such as a 3.5" controller card), it will work beautifully.

Many card clocks implemented periodic interrupt capability, many
did not.  As you might expect, the No-Slot Clock can't generate
interrupts, since it's not connected to the IRQ line.

Good luck on building a useful (compatible) multiprogramming system
for the Apple //e--it's not an easy hack!  BTW, most clock cards
didn't implement a very useful choice of interrupt rates--I've found
that the 6522 VIA chip (on some printer cards and sound cards, like
the Mockingboard), to be much more versatile (!) at generating timed
interrupts; and completely under software control.

> Much thanks in advance!

Hey, you're welcome!   ;-)

-- 
-michael

===============================================================
This is my personal opinion, and does not in any way represent
the position of my employer, etc...