Tektronix 4924 Tape Drive Emulator

[mmcgraw74]

1. the MARK command

This statement seems to suggest that MARK, as already noted, starts at the currently selected file and creates the number of requested files, overwriting the current file and adding further files until the number of requested NEW files has been is created. It then appends a LAST file and everything after that numerically is deleted? I find that really odd as a) there is a potential to inadvertently loose the currently selected file and b) there is no means to create or clear one or more files on a tape without deleting everything that comes after the current file so one could inadvertently loose an awful lot of files! KILL only works with one file so it would seem that if someone wants to clear multiple files and reset them to new within a group of existing files they would have to use KILL multiple times?

I guess this is probably all related to the limitations of working with tape, but it does mean I have to re-visit and amend the MARK command again. Before I do though, I would like to just clarify that statement. Does it really mean what I think it does?

Yes - that is the 4050 behavior on internal or external tapes.

2. Filename format

I notice that in the new TapeEM-full-1 archive you are using actual file sizes so I did a bit of work to update the functions that rename and create new files to include the length of the file in the file name rather than the record size. The number is right justified which means the filename length will be slightly longer than the existing ones. I have followed the specification here where the file length is exactly 39 characters:

https://github.com/mmcgraw74/Tektronix-4050-GPIB-Flash-Drive/blob/master/Tek-GPIB-Tape-Emulator%20command%20template.ino

The position of everything corresponds except that the numerical part on the end (file size) seems a bit longer. The digits in the first (file number) field are left justified so as to start at the first character position, but should the digits in the last field be left or right justified? Having them right justified would give filenames that are consistently 39 characters long. Otherwise they would have uneven lengths depending on the file length unless they were padded.  I am uncertain as to what was envisaged?

I thought the Tek BASIC would be consuming the file 'header' - but that is not the case.  I get the filename info from my dumps of the tape files - others from my edits to the TLIST that I then uploaded (which then have filesize instead of #of blocks).  I haven't found an issue with the SdFAT filename length being greater than the Tek BASIC header so far - but I'll make sure to test each folder before I upload a new image in the future.

3. The SINX/X picture file

I did have a bit of a look at the SINX/X picture file and program 8. I see they have been changed recently and the recent version is the one that corresponds with the discussion in your post. I can read a string with INPUT@5:A$ multiple times manually. I wrote a small program that read in a loop and did get it to run once all the way through but since then it seems to have consistently stuck at the 24th iteration which is a bit strange since in your experiment it consistently stuck on the 16th. So far I do not know the reason for this but will keep investigating.

This is the listing of the simple program that I used:

Code: [Select]

10 PRINT@5,9:"GrpR12demo"
11 FIND @5:9
13 LET B=0
15 FOR I=1 TO 124
20 INPUT @5:A$
22 PRINT I
25 IF A$ <> "" THEN 60
30 NEXT I
40 PRINT "Iterations: ", I
42 PRINT "Variables: ", B
50 END
60 B=B+1
70 GO TO 30
Please forgive the haphazard numbering!

I see your new post of today.

Yes - the only way I run now is with debug turned off.

When running on my 4052 - the USB cable is connected to my PC with Arduino IDE opened but no serial console is opened.

When running on my 4054A - the USB cable is only connected to a USB power cube.

[WaveyDipole]

1. the MARK command

Yes - that is the 4050 behavior on internal or external tapes.

Ok, I will adjust the MARK command to conform to that way of operating. Deleting the surplus files could prove to be interesting but we will see how it goes.

2. Filename format

I thought the Tek BASIC would be consuming the file 'header' - but that is not the case.  I get the filename info from my dumps of the tape files - others from my edits to the TLIST that I then uploaded (which then have filesize instead of #of blocks).  I haven't found an issue with the SdFAT filename length being greater than the Tek BASIC header so far - but I'll make sure to test each folder before I upload a new image in the future.

Its not a big deal. Even at 39 characters, the filenames are still shorter than the Tek record which is 44 characters. Allowing for the last two which are CR and DC3, it actually has 42 characters of information. As long as the file size number is contained somewhere within character positions 34-39 it should still be read as a numeric string and converted to a numeric value with spaces being ignored. The appearance of a TLIST output does seem a little neater when the final number is right justified and the filename starts and ends in exactly the same position on each row.

3. The SINX/X picture file

I see your new post of today.

Yes - the only way I run now is with debug turned off.

When running on my 4052 - the USB cable is connected to my PC with Arduino IDE opened but no serial console is opened.

When running on my 4054A - the USB cable is only connected to a USB power cube.

Thank you for confirming that. With debugs turned off and nothing being sent to the serial port, just reading the variables in a loop worked OK on the 4051. Curious why program 8 evidently halts at exactly in the same place on both the 4052 and 4054. I can't test this any further really without a real world test using the MaxiROM cartridge so will have to park it for now until I obtain a MaxiROM myself. However, I will look at whether I can improve things.

[mmcgraw74]

I just uploaded a new SD card image including the latest Games folder.

[WaveyDipole]

Thank you. I have downloaded it and will have a look tomorrow.

Now that I have almost finished building my new PC and moving everything across from the old PC tower, I am finally in a position to get back to so coding! Over the last couple of days I have re-written the MARK command to work as per the Tek. There were a couple of hurdles but it now seems to be working properly. I will post the updated code tomorrow after I have had a chance to clean it up a bit.

I am also hoping to be able to order a MaxiROM soon. I had confirmation from Bob Haas that they are in. He has been away this week but hopefully they will be going up for sale on his return.

[mmcgraw74]

Read my PM on this forum.  The SD image isn't working right.

Glad you got your PC sorted out.

[WaveyDipole]

I have now uploaded the next update which should have MARK working as it should be.

[mmcgraw74]

I never posted that we got the Tektronix 4050 computer GPIB Flash Drive working!

See my github repository for more information and the latest firmware and Tektronix 4050 Flash Drive files:
https://github.com/mmcgraw74/Tektronix-4051-4052-4054-Program-Files/tree/master/Flash_Drive

You can build my Tektronix 4050 GPIB Flash Drive yourself from my User Guide in the above repo, or send me a PM if you would like to order an assembled Flash Drive with MicroSD preprogrammed.

Remember this Tektronix 4050 GPIB Flash Drive will ONLY work with the Tektronix 4051, 4052 or 4054 vector graphics computers, since it uses GPIB secondary addresses for the commands. 

NOTE:  GPIB secondary addresses are no longer in use to command GPIB devices, the commands are now sent using GPIB data bytes.  See this other eevblog forum thread for the project that controls more modern GPIB devices:
https://www.eevblog.com/forum/projects/ar488-arduino-based-gpib-adapter/