Author Topic: Read error pages  (Read 3019 times)

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Offline ssg

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Read error pages
« on: 10:29, 27 January 11 »
I'm thinking of explaining read error codes in the wiki, however I'm not sure about the difference between a and b. Here's what I know:

read error a: signal dropped. means there was an unexpected cut in the data signal. that's why we usually get a when we suddenly stop the tape during loading.

read error b: signal not understood? usually due to head alignment or low quality magnetic signal on tape.

read error c: invalid file type?

read error d: block is too large to fit in the buffer. (given when you do a cat on large blocks)

are there any others? corrections are welcome.

Offline arnoldemu

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Re: Read error pages
« Reply #1 on: 12:07, 27 January 11 »
I'm thinking of explaining read error codes in the wiki, however I'm not sure about the difference between a and b. Here's what I know:

read error a: signal dropped. means there was an unexpected cut in the data signal. that's why we usually get a when we suddenly stop the tape during loading.

read error b: signal not understood? usually due to head alignment or low quality magnetic signal on tape.

read error c: invalid file type?

read error d: block is too large to fit in the buffer. (given when you do a cat on large blocks)

are there any others? corrections are welcome.

read error a is down to the timing of the signal, so the timing is too fast, or signal dropped.

read error b is checksum incorrect (so data read ok, but when checksum was calculated then compared to checksum on cassette, they were different).

read error d is block too large.

read error c seems to be used with "CAS CHECK". This is where you are comparing data in memory with data written to tape. So effectively a verify that data was written correctly.
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Offline ssg

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Re: Read error pages
« Reply #2 on: 13:13, 28 January 11 »
Ok I added the initial version. Firmware disassembly excerpts could be added in the future to prove in which exact cases they are used.


http://cpcwiki.eu/index.php/Read_error_codes

Offline Gryzor

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Re: Read error pages
« Reply #3 on: 15:45, 31 January 11 »
Thanks for adding it :)

Tip: take a look at http://cpcwiki.eu/index.php/Special:WhatLinksHere/Read_error_codes : this shows that no other articles link to the one you created. While your effort is visible when someone searches for it, it's not easy to get there through other articles... so it'd be great to add links to it to any relevant pages you can think of - guides, troubleshooting, hardware even...

Online Bryce

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Re: Read error pages
« Reply #4 on: 16:24, 31 January 11 »
I've added links from the two DIY tape sockets I did:

http://www.cpcwiki.eu/index.php/DIY_464_External_Audio_Socket

http://www.cpcwiki.eu/index.php/DIY_Plus_Tape_Socket

But it needs to get added to a main software / hardware page directory too.

Bryce.

Offline Gryzor

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Re: Read error pages
« Reply #5 on: 18:22, 06 February 11 »
Thanks mate!

As for the main soft/hard pages, hm, maybe it's not the best place... we're really lacking a 'troubleshooting' ueber-category I guess?

Online Bryce

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Re: Read error pages
« Reply #6 on: 18:42, 06 February 11 »
At the moment, the only trouble-shooting is lumped in at the bottom of the DIY & Repair, but as most trouble shooting is hardware related, it's probably still the best place to have it, it just lacks in content?

Bryce.

Offline Gryzor

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Re: Read error pages
« Reply #7 on: 18:47, 06 February 11 »
You mean DIY&Repair? Probably... could even rename it to DIY&Troubleshooting, which somehow I feel also covers repairing...

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Re: Read error pages
« Reply #8 on: 20:25, 06 February 11 »
Nah, DIY & Repair is the better description, troubleshooting is just a step within the repair process, eg: A read error on the disc, Troubleshooting = Does the drive belt need to be replaced, Repair = The description of how one changes the belt.

The other option would be to put DIY in its own category and make a new Troubleshooting and repair category? But there's very little content at the moment to justify this.

Bryce.

Offline Gryzor

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Re: Read error pages
« Reply #9 on: 10:43, 07 February 11 »
Nah, you're right abot that.

Offline mr_lou

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Re: Read error pages
« Reply #10 on: 18:35, 05 July 15 »
Sorry for reviving an old thread, but I have a question about read error codes:

Is there no way at all a "Read error d" can occur when trying to RUN a file? Will it always only occur when CAT'ing a tape?
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Offline mr_lou

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Re: Read error pages
« Reply #11 on: 09:59, 27 September 15 »
Bumping this again.
Really no one knows?

Is there no way at all a "Read error d" can occur when trying to RUN a file? Will it always only occur when CAT'ing a tape?

I'm asking because of a memory I have that I'm writing about in "8bit Stories". If a "Read error d" is not possible when trying to RUN a file, then I remember wrong.
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Offline EgoTrip

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Re: Read error pages
« Reply #12 on: 11:17, 27 September 15 »
I have never seen a read error d when run, only cat. It always loads long blocks fine (unless there is a read error a or b).

Offline Johnny Olsen

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Re: Read error pages
« Reply #13 on: 12:56, 27 September 15 »
This is what I could find in Soft 968 Firmware Guide.
I have only seen read error d if I cat a file saved with "amsback"


       c. Error messages.

           Rewind tape

 While searching for a block of the file being read, a higher  numbered
 block than that required has been found. The required block  has  been
 missed. This message is often produced  after  a  read  error  in  the
 required block when the next block is found.


            Read error X
            An error of some kind occurred whilst reading from tape. The tape
            should be rewound and the block played again. The X is  a  single
            letter indicating what kind of read error occurred:
            'a'           Bit too long        An impossibly long one or  zero
                                              has been measured.  This  often
                                              indicates reading past the  end
                                              of the record.
            'b'           CRC error           Data   was   read   from   tape
                                              incorrectly.
            'd'           Block too long      The data record  contains  more
                                              than the expected 2048 bytes of
                                              data.
            Write error a
            An error occurred whilst writing to the tape. There  is  only  on
            possible write error. This indicates that  the  Cassette  Manager
            was unable to write a bit as fast as was  requested.  This  error
            will never occur unless the user has set the write  speed  beyond
            the maximum possible.


Offline AMSDOS

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Re: Read error pages
« Reply #14 on: 07:55, 28 September 15 »
I recall that Read Error D when I was doing Tape To Tape Transfer of my AMSOFT games using JL-Copy. The First Block was ok, as soon as Block 2 would come up, Read Error D appeared when CATaloguing the Tape.

 

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