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Bacchus
Registered: Jan 2002
Posts: 154 |
Drive code: Detect missing disk...
I have detecting missing *device* covered. This logics work really well:https://codebase64.org/doku.php?id=base:reading_the_error_chann..
Also, checking if a file exists, one would expect that a plain Open would do the job, but you basically need to read the first byte and checking the Status. But then you have established that.
But what is the easiest way to detect if the device contains a disk? Let's say we have established that there is a disk in the drive. I can start reading a file, but then I don't know if the error will tell me if the file or the entire disk is missing.
Should I do a block read, start reading the directory or what is the general suggestion?
/Bacchus |
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Krill
Registered: Apr 2002
Posts: 2822 |
What do you actually want to achieve?
Why does there need to be a distinction between file not found and no disk inserted? |
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Comos
Registered: May 2004
Posts: 71 |
@Bacchus,
the test device routine you have is serial dependant, if you want to have it universal, it can be rewritten in kernal aswell. |
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Bacchus
Registered: Jan 2002
Posts: 154 |
@krill I want to load and save stuff to disk as part of a program, and that program needs to handle the situations where there is a save problem. Formally no need to differentiate between the two cases, but if you select a device you might want to capture that this is a device not available and I am also keen to capture no disk in the drive before I start the actual save.
@cosmos The use case is serial with a drive. No need to generalize it beyond the actual use case.
I did a test program where I implemented the above, but there is still issues when the same code is implemented in the program. :-P
/Bacchus |
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Krill
Registered: Apr 2002
Posts: 2822 |
Quoting Bacchusif you select a device you might want to capture that this is a device not available and I am also keen to capture no disk in the drive before I start the actual save. What would be the difference between erroring out after an init command before saving vs. attempting to save and then erroring out? |
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Bacchus
Registered: Jan 2002
Posts: 154 |
Gunnar, you come from a different perspective.
You do your thing and put the loader out for others to use. I am retrofitting stuff, meaning I need to wedge in my stuff as smoothly as possible. I might also not control what happens after a certain point unless I open up more patching with potential side effects.
So I prefer to do my stuff and secure things are as good as I can make them, and then I release the thing, not being sure I can regain control if it bugs out at a later stage.
Not sure that argument holds water, but also there is an inner loop loading five different files. Letting them all fail will take a long time. Wedging in stuff there is tricky so I prefer to do it this way this time ...
The things with that piece of code I have done is that it tells "device not present" from "disk not present", and that *looks* nice :-)
/Bacchus |
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Comos
Registered: May 2004
Posts: 71 |
Quoting Bacchus
I did a test program where I implemented the above, but there is still issues when the same code is implemented in the program. :-P
What kind of a issue? |
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Krill
Registered: Apr 2002
Posts: 2822 |
Quoting Bacchusthere is an inner loop loading five different files. Letting them all fail will take a long time. Wedging in stuff there is tricky so I prefer to do it this way this time ... Retrofitting or not, what i was saying is that i see no advantage of checking for disk-not-present prior to saving, as saving itself does that check implicitly, too.
This is also independent from any inner loops handling multiple files. |
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Bacchus
Registered: Jan 2002
Posts: 154 |
Quote: Quoting Bacchus
I did a test program where I implemented the above, but there is still issues when the same code is implemented in the program. :-P
What kind of a issue?
@Cosmos Can't really describe it perfectly but it feels like the commands aren't concluded properly, and the drive isn't ready to accept new commands. The detect disk command works arbitrarily. Sometimes it does and sometimes not (possibly depending on what happened before). Trying to send an "I" commands after my detection routines, I simply get an error. In VICE I can switch to DEV 8: and do M 0200 to see the status message, and sometimes that is Syntax error. That could sometimes happen if I send commands in the wrong case (common issue I have when messing with drive code).
@Krill I fully sympathize with this point of view and I will onboard it when considering the task ahead. Would be stupid not to :-)
Can be agree that if $98 is $00, then I have closed all files I have opened, right?
/Bacchus |
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Krill
Registered: Apr 2002
Posts: 2822 |
Quoting BacchusCan't really describe it perfectly but it feels like the commands aren't concluded properly, and the drive isn't ready to accept new commands. The detect disk command works arbitrarily. Sometimes it does and sometimes not (possibly depending on what happened before). I think it's important to error out at the earliest possible chance. So i'd check $90 after every command that might fail, plus OPEN returns an error flag via the C flag. On error, of course, need to properly clean up, too. |
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Comos
Registered: May 2004
Posts: 71 |
Quoting KrillI think it's important to error out at the earliest possible chance. So i'd check $90 after every command that might fail, plus OPEN returns an error flag via the C flag. On error, of course, need to properly clean up, too.
Besides $90 it's possible to readout accu for error code aswell in certain calls. |
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