[Coco] DriveWire

[Bill Pierce]

Tormod, what you are probably not aware of is that VCC does not speed up the hardware clock. When the CPU is overclocked, the hardware clock remains the same speed and is not accelerated with the CPU. So any sofware using the hardware clock will not be affected, but software using software timing loops will be affected. I'm not sure if DW drivers are affected by this, but I run at 89mhz in NitrOS9 most of the time and have seen no timeout issues.
A good example of this in RSDOS is "Lyra" which will play MIDI music at the exact same speed at 89mhz as it does at 1.89mhz. Lyra uses a "sleep" instruction between notes which is based on the hardware clock. Musica II on the otherhane, will speed up playback as the music is played via a software timing loop.
An OS9 example is "Ultimuse3" which will play MIDI at the correct speed with overclocked CPU.
In both programs, with overclocked CPUs, the screen refresh and graphics are alomist instantaneous, but the MIDI clock remains the same.

 On the other hand, unchecking the "Throttle Speed" in the display tab of the configuration (not recomended) will speed up ALL aspects of VCC; timing, cpu, key reads etc. This is almost unusable with todays fast computers but was a benifit with older, slower machines.

 


Bill Pierce
"Charlie stole the handle, and the train it won't stop going, no way to slow down!" - Ian Anderson - Jethro Tull

 

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-----Original Message-----
From: Tormod Volden <lists.tormod at gmail.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Fri, Feb 19, 2016 4:17 pm
Subject: Re: [Coco] DriveWire

On Fri, Feb 19, 2016 at 7:28 PM, Bill Pierce via Coco<coco at maltedmedia.com> wrote:> Tormod, to correct a misperception, The becker port runs at the same speed on emulators regardless of overclocking speed.> The Becker port uses TCP which is handled by the PC, not the emulated machine. The data packet is ALWAYS sent at the fastest possible speed the PC itself can handle regardless of the speed of the emulation. The TCP transfer is an "outside" process and not actually part of the emulation.Yes, I am well aware of this.What I was talking about was the timeout in the Becker routines in theclient. If it doesn't hear back from the server in a certain time(nominally 0.25s) it should abort and report failure to the caller.The time to wait is determined by CPU cycles. So if you run in anoverclocked emulator the X number of cycles will have passed muchquicker than 0.25s.Tormod-- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco