Pentagon-128

Hello Sonic in one of the zx-ferrum numbers I placed the correct reset circuit to zero page for the Pentagon. Yeah, I found it: ZX-Ferrum #2 article "Pentagon - hidden reserves."

Hello, Error404 Err> HD and VG93 are not linked to each other in any way. How can they not be linked if below you write about twice the clock frequency? Err> If the operating system supports setting the disk format, then that's it Err> will work just fine. CP/M can do it. There for this purpose on every floppy disk Err> there is a boot sector with a Disk Parameter Block. Not in all versions of CP/M In Corvette, yes, but in Robotron 1715, for example, no, although the disk formats are the same. Err> Increase the clock rate on the BG by half, write in boot that you have 10 1k sectors Err> to the track (+ double a couple more parameters in the boot, for the rest Err> CP/M will configure itself) and you have 1600k instead of 800k. I could do CP/M Err> switch the VG clock itself using a bit of the drive port - select the desired one Err> mode, simultaneously working with both 800k and 1600k floppy disks (FDD 3.5" Err> of course). But I couldn’t do this on a non-turbocharged Quorum. The reason is that data from HD disks arrives at a speed of 500 kbps, in contrast to DD, where the speed is 250 kbit/sec (4 microseconds per clock). In this case, accordingly, the speed with which you need to read data from VG93 will be respectively 500/8 kbytes/sec and 250/8 kbytes/sec.The maximum speed at which a non-turbocharged Spectrum can read them about 300/8 kbytes/sec. Either turbocharging or line interruption work can help here data readiness.

Hello Allegro All> 1. Fast positioning + fast reading (writing is standard). All> 2. HD will not read, even if you install an HD drive - VG93 does not All> supports. All> HD and VG93 are in no way related to each other. If the operating system supports the setting to the disk format, then everything will work fine. CP/M can do it. There for this on Each floppy disk has a boot sector with a Disk Parameter Block. Raise the beat on BG twice, you write in boot that you have 10 1k sectors per track (+ there in the boot also double a couple of parameters, CP/M will configure the rest itself) and you have 1600k instead of 800k. My CP/M was able to switch the VG clock itself using a bit of the drive port - select the desired mode, simultaneously working with both 800k and 1600k floppy disks (FDD 3.5" of course).

Hello, The Exploited The> I don’t understand what the topic is about? maybe we should all just get together and buy The> beer and go to the author, live for a couple of weeks and fix his computer. And the wife of all of you with a broom, a broom. :v2_wink2:

Hello caro car> How are they not coordinated if below you write about twice the frequency car> clocking? car> Oh, well, yes. I just didn’t count the second quartz and half of LR1 as a revision. ;) And then, this is still not some special property of VG93. She doesn't care how much give the beat, that’s what it works for. car> Not in all versions of CP/M car> In the Corvette, yes, but in Robotron 1715, for example, no, although the disk formats car> match. car> again you're right. My BIOS was in Corvette ancestors. To work with floppies Pro I had a resident sitting on BIOS vectors, which when trying to read sector 0 of track 0, I slipped a “pseudoboot” for the drive where there was a disk without boot. But again, this is not a property of VG. car> But I couldn’t do this on a non-turbocharged Quorum. car> The reason is that data from HD disks arrives at a speed of 500 car> kbit/sec, car> in contrast to DD, where the speed is 250 kbit/sec (4 microseconds per clock). car> At the same time, according to the speed with which you need to read data from VG93 car> will be 500/8 kbytes/sec and 250/8 kbytes/sec, respectively.car> The maximum speed at which a non-turbocharged car can read them car> Spectrum about 300/8 kB/sec. car> Either turbocharging or interruption work can help here car> data readiness lines. Well, yes, this is implied, I did not write about it. Already 5 MHz is enough for 1600k. At 3.5 MHz I used 7 1k sectors per track - after the death of real Now there is no place to read floppy disks in this format, hehe. :v2_smile: