----- Original Message -----
From: "Dilwyn Jones" <[email protected]>
To: <[email protected]>
Sent: Friday, February 04, 2011 11:55 AM
Subject: Re: [Ql-Users] IDE versus SD card
data transfer from an SD card takes 0.4 microsecond per Byte in the most
simple mode, while the minimum cycle of the QL bus is 1.0 microsecond. So
both IDE and SD card are faster than the QL bus.
SD cards are smaller and cheaper than IDE drives. Both offer more size
than a QL filesystem can use.
If a fast SD card interface & driver for the QL was here: Where would be
the point in IDE for the QL? Apart from being too laid-back to copy data
to SD card once :-)
I understand keeping the microdrive for antiquarianism, because it was
part of the original QL. But that doesn't count for IDE. Otherwise it
would be quite simple for me to implement.
All the best
Peter
This is a good point. When I made the comment about a new Qubide not being
of much use because hard disk drives in IDE format were not available much
nowadays, I didn't take into account the availability of flash card
interfaces (many of which offer quite high capacity of storage at good
prices now) and IDE conversion leads and kits.
The idea of installing your SD/MMC card interface in one of the two
microdrive slots is actually quite attractive - using the MDV slot in the
QL case to insert a modern memory card with a GB or more instead of a 100K
MDV would instantly modernise the look and feel of the QL! Plus of course
the memory card could be unplugged and files transferred to another system
when required.Conceivably, those like myself with many QL CDs could
probably copy the files off those to a SD card and just plug in the "CD"
required if software was available which could read a QXL.WIN (e.g.
Duncan's QCDEZE could be modified perhaps to work with your interface?)
Good luck with this project Peter, if you do decide to go ahead with it.
Dilwyn Jones
How many erase/re-write cycles is each bit in modern flash memory good for
nowadays? SD cards would be great for storing libraries of programs and data
that don't change frequently, but what about using them, for example, for
frequently changing temporary files generated by running programs (the sort
of thing we should probably use RAMdisks for given enough RAM)? Do
hard-disks still have the advantage there?
Ian.
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