Faster CP/M - What's the Problem?

[airship]

Okay, this is from the Wikipedia article on the C128:

Unfortunately, the C128 ran CP/M noticeably slower than most dedicated CP/M systems, as the Z80 processor ran at an effective speed of only 2 MHz (instead of the more common 4–6 MHz) and because it used CP/M 3.0, whose complexity made it inherently slower than the earlier, more widespread, CP/M 2.2 system. From the source code of the C128 CP/M implementation, it is clear that the engineers originally planned to make it possible to run CP/M in the "fast" mode as well, with the 40-column output turned off and the Z80 running at an effective 4 MHz; however, this did not work on the released C128 hardware.

So.. what's the problem? Why didn't it work?

[xlar54]

Guessing it was just a timing issue of the 4Mhz processor, running against the other slower chips.

[airship]

I know the maximum clock rate for the system hardware is hardwired to be just 2 MHz, so I know that's the maximum upper limit. I also realize that even if you have the VIC-II turned off, it still has to interrupt for a short time every 1/60 second to refresh the dynamic RAM. But its my understanding that CP/M still runs considerably slower than "just a bit less than 2 MHz". Do I have this right? If so, why?

[BillBuckels]

So.. what's the problem? Why didn't it work?

This sounds like an article worthy of being written.

Nigel Parker nigelp2k@yahoo.co.uk the publisher of Commodore Free Magazine http://www.commodorefree.com
wrote me this AM asking for contributions for an up-n-coming issue of C= Free with a CP/M theme due in two months.

Mr. Parker would likely be thrilled if some of us geniuses contributed a page or 10.

Mark, you seem to have lots of ink left in that pen of yours. I realize that you hide in an area of Norway somewhere in the US now but I know that you occasionally get in that Airship of yours and take a ride over to other parts of the world because I saw you in usenet just the other week.

I pointed Nigel over here. I'd prefer if some of the Real C-128 People told the CP/M tale. I don't know where Von Ertwine is these days but I know you and Lance and the rest of the folks here could probably carry-this-off with a little (WAY) more content than I am capable as a newbie.

Unless you have writer's cramp or writer's block in which case y'all are going-to be reading more self-agrandizing spam all about how Bill Buckels tamed CP/M for the masses in some emulator in Windows XP with Aztec-C again:)

Kindest Regards from the Land-Up_over,

Bill bbuckels@mts.net

[RobertB]

Nigel Parker the publisher of Commodore Free Magazine wrote me this AM asking for contributions for an up-n-coming issue of C= Free with a CP/M theme due in two months.

---------------------------- Original Message -------------------------
Subject: Commodore Free and CP/m
From:    "nigel parker"
Date:    Wed, December 10, 2008 11:09 am
--------------------------------------------------------------------------

Hello, nearly Christmas :-)

I have been trying in vain to contact anyone who is still using or who has used CP/m on Commodore hardware. I have followed some threads but am unable to get anyone who would write a little something up for Commodore Free.

I was hoping for a Cp/m issue. I have some text but would like another 10 pages or even more as Cp/m is so under promoted.

[The] user can reach me with with the following address

commodorefree(at)commodorefree.com

Thanks
Nigel
www.commodorefree.com

[airship]

I used to review CP/M stuff for INFO, but it's been a long, long time since I last fired it up.

I think Lance is the resident expert.

[Blacklord]

I used to review CP/M stuff for INFO, but it's been a long, long time since I last fired it up.

I think Lance is the resident expert.

I wouldn't say expert But I play with it a bit - still do on both the 128 & on an XT (NEC V20 equipped, so runs CP/M-80 'natively'. Using CP/M on the PC is more 'pleasureable' than my 128 - at least the XT has a hard drive

cheers,

Lance