BBC Basic for Z80

discussion of beeb/electron applications, languages, utils and educational s/w
torrind
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Re: BBC Basic for Z80

Post by torrind » Thu Feb 15, 2018 9:51 pm

Hi All,

Whilst not all bad news - In my continuing quest to understand this BBC wizardry, I seem to take 2 steps forward and 1 back :D

Another question for you good folk.

I have successfully imported the JGHCPM1 image and created a HDBIOS. However when I boot into the C drive, It can take approx 2 mins for the C prompt to appear. When accessing the C drive, its very S L O W. I can copy files to it, but only very infrequently. Most of the time, I get random graphic artefacts appear on the screen and my BEEB hangs. If I press Break or a combination of Shift `break, I get a 'bad sum' error. Thinking that im getting some sort of contention with other ROMs, I've disabled everything except the RAMFS ROM and its accompanying ADFS ROM for Datacentre use only.

Any ideas? If I can overcome this hurdle, I'm all set :)

Thanks in advance.

Darren

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jgharston
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Re: BBC Basic for Z80

Post by jgharston » Fri Feb 16, 2018 2:16 am

torrind wrote:I have successfully imported the JGHCPM1 image and created a HDBIOS. However when I boot into the C drive, It can take approx 2 mins for the C prompt to appear.
Yep, well what would you expect, building a disk map for a 8M disk compared to building a disk map for a 400K disk? :) I've just done a quick test and it took 60 seconds from Ctrl-Break to C0> prompt.

*RFSLoad 0 JGHCPM1/ss
*RAMTRAP
*CONFIG. TUBE
*CONFIG. EXTUBE
Ctrl-Break
Acorn CP/M 2.2 - HDBIOS 1.24
(count to 60)
SJCCP version 1.40

C0>
torrind wrote:When accessing the C drive, its very S L O W. I can copy files to it, but only very infrequently. Most of the time, I get random graphic artefacts appear on the screen and my BEEB hangs. ...
On thing that will slow hard drive access down is if the current filing system is not ADFS (or the filing system the hard drive image is on) as whenever the BIOS switches to ADFS to access the disk image, ADFS will flush its buffers. If you start with Ctrl-A-Break to start off in ADFS then hard drive access is faster as you're in ADFS, but floppy (or RAM floppy) is slower due to the opposite effect. You can see the difference directly if you use combinations of swapping between A: and C: and DIR'ing the opposite drive. Eg A:, DIR will be fast, C:, DIR A: will be slow, etc. That's due to how CPM and the CPM BIOS work.

I've not experienced the other issues you mention. I've had CPM+RAMFS+ADFS working on my Master+AcornZ80. I'll do some tests, but it will have to be next week as I'll be a work for the next few days (in fact, I should really be in bed right now). I'll see if I can set up a system on my laptop.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

torrind
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Re: BBC Basic for Z80

Post by torrind » Fri Feb 16, 2018 8:25 am

Thank you for the explanation regarding disk mapping, I really should have realised. Certainly makes things much clearer. :oops:

I'll check to see if i'm using ADFS as the current filing system and see what happens wrt speed. Thanks for the offer of help for the on-screen artific issue though.

torrind
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Joined: Fri Dec 01, 2017 4:57 pm
Location: Bristol
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Re: BBC Basic for Z80

Post by torrind » Wed Feb 21, 2018 10:18 pm

Further to my last post, attached are screenshots of the errors I now get. If I attempt to PIP files from B: drive to the C: drive, then I get these random channel error messages and artefacts on the screen. Now and again I get a clear shot and can copy two or three files before my B: drive gets corrupted and the transfer errors. I've tried disabling roms, removing roms, swapping them around in different banks to no avail. Help! :?
Attachments
IMG_3500.jpg
IMG_3503.jpg

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