openGL + SCSI

hi - this isn’t really an opengl question but it kinda relates to it. i was thinking about how frames tend to skip when opengl has to wait for the hard drive to read new textures from the disk. if your hard drive was a SCSI drive, would this happen? i mean, with IDE, the processor has to do a lot of work compared to a SCSI which doesn’t require hradly any…i don’t have a SCSI or i could check it myself. does anyone know? also, if you put your texture loading code into a new thread, would this decrease the problem?

If you have IDE bus mastering drivers, the CPU should not have to do much. At least in NT and 2000, disk access is usually not noticeable (unless the program is waiting for the data, of course). In Windows 95 / 98 sometimes the whole system freezes when you’re accessing drives (even with bus mastering drivers).

Windows comes with good bus mastering drivers for older Intel chipsets (ex, BX). For newer and non-Intel chipsets, check the manufacturar’s sites (Intel for the UltraATA drivers (ex. 815 chipset) and VIA for the 4-in-1 drivers).

If your program is waiting for the textures, naturally it will have to freeze until they’re available. The way to avoid this is to load them before they’re needed. Using a different thread would let the OS “multitask” the loading and the main program.

BTW, I use both IDE and SCSI drives and presently there isn’t such a huge difference as some years ago. The big advantage of SCSI is interleaved read & write commands, which will make a difference is busy servers. In most situations, the SCSI performance gain doesn’t justify the price.

Rui del-Negro