Login
Back to forumSee the full topicGo to last reply

Posted By

MMS
on 2013-08-09
18:06:23
 Re: Z80 GUI: SymbOS

wow, i am sorry that this topic become so serious. happy
about speed. It does not help too much if you have an extreme fast device, but your pc can utilize only 1% of it due to slow interconnection between them.
JamesD, I am pretty sure, that you know more about the systems than me. But calculating theoretical reading speed may completely misleading us from real life performance. 1541 was a good example: based on rotation and track calculations it may read 20000byte/sec, but real life performance is only 400.
If you connect the exactly same SATA3 HDD to a sata1,sata2 or sata3 controller, you may notice completely different reading speeds, though the RPM of the drive is exactly the same! THAT important is the interface, you just neglect to take care, pushing to use the rotation speed calculation.
The same way it is not expected to get 1000mb/s tranfer speed from a hdd connected to a c64 via IEC,just because it has 5400RPM. the handshaking,flag, etc handling too much of the CPU time. With DMA it is different, That's why i found SD (or CF) card connected to eZ80 so interesting.

It is too bad, that Commodore put speed into real focus only after 128&1571.
I know that 1551 was faster, but NOT that much faster as it should be with 8 data lines.
why they did not apply an existing IEE488 interface to Plus/4? More and bigger drives, no additional development cost, same or better speed, compatibility. Anyone who is familiar with development knows how much more it cost to develop and validate something completely new compared to modify something that already exists(in PET range)



Back to top


Copyright © Plus/4 World Team, 2001-2024