patchGNU MIX Development Kit - Patches: patch #9775, Support IOC commands for disk/drum...


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patch #9775: Support IOC commands for disk/drum devices

Submitter:  Kevin Brunelle <brunk23>
Submitted:  Wed 20 Mar 2019 12:43:28 AM UTC
Category:  None Priority:  5 - Normal
Status:  Done Privacy:  Public
Assigned to:  jao Open/Closed:  Open

Tue 09 Apr 2019 01:42:15 AM UTC, comment #1: 

Hi Kevin,

Looks good: i've applied the patch to master.  Thanks!

Jose Antonio Ortega Ruiz <jao>
Group administrator
Wed 20 Mar 2019 12:43:28 AM UTC, original submission:  

There is a minor fix included with regards to tape devices.  The test was failing if M == 0, when it should fail when M != 0.

NOTICE: This patch changes the behavior of the VM and changes the function parameters for the ioc_ function.  Documentation changes are included.

Permits the following:

     IOC   0(8)
     OUT   ADDR(8)      Write block from ADDR into disk[BLKNUM]
     IOC   0(8)
     IN    ADDR(8)      Read block from disk[BLKNUM] into ADDR
BLKNUM  CON  45000      Example possible block on disk

I was having an issue writing a block to a drive and then reading back the same block.  Because it is impossible to move the SEEK_CUR pointer backwards on a disk device, there was no way for a program to read back a block that it wrote to a disk without restarting or fiddling with ~/.mdk/disk?.dev files and symbolic links.

I have added a function parameter to the ioc_ function and used it to pass the value of rX to ioc_.  This permits us to use IOC commands to move the read/write head on a disk/drum device.  I believe that this conforms to the potential meaning of Knuth's description of IOC for disk/drum devices.

I have put in tests to verify that rX is positive and M = 0.

I have updated the documentation to reflect this new behavior.

This makes disks much more usable.

Note: I won't be offended if this patch is rejected because it changed the behavior of the VM. I think it fits the spirit and enhances the functionality in a way that some might find useful.  I wanted it for something I was working on, and I felt others might want the same.  The thing with the paper-tape should be fixed, though.

Kevin Brunelle

Kevin Brunelle <brunk23>


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Attached Files
file #46591: added by brunk23 (6KiB - text/x-patch)


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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-04-09 jao StatusNone Done
        Assigned toNone jao
    2019-03-20 brunk23 Attached File- Added, #46591

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