RT11 BAD Files

[David Lochlin]

Gooday, I notice a number of files displayed on RT11 DK0: are marked as BAD. Is this unique to me and maybe caused by my tinkering, or were they like that on the downloaded image?

Notable of these is gbasic.sav and gbasic.obj. Is there a way of replacing these with GOOD files(provided I can find a source). Or do I burn a new PiDP11 image?

Tks  Dave

[isy...@gmail.com]

Hi Dave,

 Firstly, where did you get the image from? In general, .BAD files are usually named FILE.BAD and result from an INIT/BADBLOCKS command.

 The second possibility which I used to use is to mark files as .BAD if they didn't run or didn't read correctly.

 I am intrigued by your note that they are named gbasic.* Gbasic contains code to drive the VT11 hardware and is not typical name

 for this app. It is described in dec :: pdp11 :: basic :: DEC-11-LBACA-D-D basicRTlangRef Oct74 : Free Download, Borrow, and Streaming : Internet Archive

 However, images I have created do contain this file. I would expect that a version of GBASIC.SAV should be on the disk as well. If so,

 You can just delete these files as they may contains errors....Unless 

Finally, you may be referring the the filedate field in the directory listing. All this means is that the date in the file header is invalid.

eg:

.dir g*.*
 
GIDIS .SAV    72  20-Dec-85      GETSTR.FOR     2  20-Dec-85
GEOWAR.BAS    10  15-Oct-99      GIRL0 .PIC    37  15-Oct-99
GIRL1 .PIC    19  15-Oct-99      GIRL2 .PIC    21  15-Oct-99
GOLF  .BAS    13  15-Oct-99      GOMOKO.BAS     5  15-Oct-99
GUNNER.BAS     4  15-Oct-99      GBASIC.OBJ    36    -BAD-  
GBASIC.SAV    49    -BAD-        
 11 Files, 268 Blocks
 9532 Free blocks

You can ignore this error. And, I suspect you may have found one of my RT11 images!!!!!!

Regards, Ian.

[Jonathan Harston]

It could well be that the dates are after 1999, but you are using a DIR.SAV
from before v5.6 which doesn't understand post-1999 dates. You can simply
copy DIR.SAV from a v5.7 distribution.

Similarly with DATE.SAV, but that needs to match your hardware.

[David Lochlin]

Thanks for your reply Ian,

 my image was downloaded from the link as specified in the Obsolescence PiDP11 Getting Started document located at  pidp.net/pidp11/pidp11.tar.gz
You are correct in assuming the BAD is contained in the filedate field(so nothing to worry about) and I incorrectly assumed that GBASIC was RT11's BASIC. In any case when I did run BASIC I was bounced to the simh prompt so have assumed there maybe a problem with the image version. I have since found another version of BASIC at https://web.archive.org/web/20120815032628/http://www.pdp11.co.uk/library/local/pdp-11/RT-11/languages.dsk so I downloaded that and copied to my RT11 DK0: directory and BASIC works fine so far. So, I have learned quite a bit in going through this exercise. I am sure I will have more questions in the future so thanks for the guidance.

Regards Dave

[David Lochlin]

Are you referring to the filedate marked as BAD issue. In my ignorance I am assuming that some sort of date compatibility causes this. Way above my knowledge base at the moment but I tanks you for your assistance.

Cheers Dave

[isy...@gmail.com]

Hi Dave,

 Yes, the systems archive at pidp.net/pidp11/systems.tar.gz does contain one of my images with all sorts of stuff on it. However, I am intrigued by your comment that trying to run BASIC dumped you back to the Simh prompt.

 This is a known RT11 wrinkle in that if you just type 'BASIC' at the RT11 . prompt, Simh will halt. But to run it correctly type 'R BASIC' and it will be fine. Is this what happened? I would note that GBASIC can do this as well.

 As a general rule, to run an app under RT11, use R <app>. I suspect the 'R' command adjusts the core control block at location 40. Overall, this is likely due to version incompatibilities. I would note that

 the (old) version of BASIC (V01B-2) runs fine under RT11 V4 but not RT11 V5.x. I assume you now have BASIC V02-03 which should be fine.... (There are other versions on the language disk as well!!!)

 Sorry for the detail but this info can help other people as well......

Regards, Ian.

[David Lochlin]

Ian,

I have learnt so much in a week of playing with RT11 that I now always use the RUN prefix now but a week ago I may have been trying it without the R(UN), who knows! I am now running V02-03 without problems. My next challenge is to learn some assembly language so I'm sure I'll be back with some more questions.

Thanks Dave