Hoe "langzaam" zou het allemaal gaan ?
Uit de teksten en linken hierboven gegrepen:
PIO modus
[...]
PCMCIA/CF cards DO NOT SUPPORT DMA; they can only be used in pio mode.
[...]
Unfortunately, CompactFlash only provides a PIO (programmed-IO, ie - not DMA) interface. The lack of DMA support makes access very CPU intensive (apparent in the HDTach scores below). This also appears to have a second, less obvious consequence. CompactFlash on a IDE interface is recognized by both Promise and Highpoint IDE raid controllers, but is not considered a valid device. Unfortunately, this prevents the formation of a simple Windows RAID, as shown in the picture below. (Note: We are still looking to confirm the cause of this; at the time of writing both raid controllers simply would not not recognize CompactFlash as a RAID-worthy device). CompactFlash can also be used as a removeable media to replace the traditional floppy drive using a USB adapter similar to the Sandisk SDDR-31. This adapter has solid driver support for Windows and Linux; however, it lacks the boot support of a conventional floppy.
The relative speeds of CompactFlash (CF) over both USB and IDE was compared to that of three more conventional hard drives. A Quantum 20GB AT Fireball 7200rpm drive, a 9GB older Quantum 5400rpm drive and a 20GB IBM Travelstar 40GN 4200rpm laptop drive were compared using Sisoft Sandra filesystem mark for general performance and HDTach for more detailed results. All tests were conducted under Windows 2000 with most efficient transfer mode (DMA if possible) selected. For Sisoft Sandra, a NTFS file system was used. Sisoft Sandra conducts it's tests within a file, making it susceptible to effecencies of the files system. HDTach makes more low-level calls to directly access the drive, thereby bypassing the filesystem..
Due to it's solid state construction CompactFlash never has to wait for a platter to rotate or heads to move, and consequently has much faster access times than a conventional hard drive. Unfortunately, it can only sustain about 15% of the data throughput of a traditional drive. The limitations of the USB interface are apparent as the IDE connections can sustain almost twice the data throughput with a dramatically faster access time. However, due to the reliance on a polled (PIO) interface, the IDE adapter consumes more than ten times more processor time than any of the other listed interfaces. It is interesting to examine the fluctuations in access speed on a conventional hard drive, versus the constant rate of a solidstate device as is shown in the following HDTach Results.
Meer leesvoer:
http://www.minervatech.net/reviews/silent_demo/
Dit oude koetje gaat weer bijkomen van het geschop en gaat ontspannen in de schuur.
[
Voor 109% gewijzigd door
Verwijderd op 11-11-2003 19:32
]