A little remark on "conventional" buffering for QL mass storage drivers.
The situation for modern hardware is completely different than for floppy and microdrive. For example, reading a block directly from SDHC card on the QL is NOT slower than reading it from RAM! Modern SDHC cards are so fast, that read accesses can happen back-to-back. (And access to the QL ROM area, used by QL-SD, is even faster than to the QL internal RAM area.) QL-style SLAVE block buffering would in most cases not speed up, but slow down access to an SDHC card! Especially if the number of SLAVE blocks is allowed to grow until all free RAM is used - which is the convention. This effect had already been seen on the Q40/Q60 IDE harddisk driver, where SLAVEing slowed down reading large files extremely. Without a quick & dirty workaround that reduces buffer space, the IDE driver would have become almost unusable. Ideally, a new compromise between buffer management overhead and the benefit of abstracting very short scattered accesses from the hardware block access level would be nice. Peter _______________________________________________ QL-Users Mailing List
