SCSI Controllers

In theory, you shouldn’t have any problems with a SCSI card, because all SCSI cards are written to exacting technical specifications.

If you believe that, we have some swampland in Florida for you.

The fact is that SCSI cards are not all alike, and you can’t assume that because you have a SCSI controller on your PC, you’ll be able to use Linux with no sweat. Most low-end SCSI controllers were designed to interface with a CD-ROM drive, not necessarily a hard drive or another SCSI device.

These SCSI controllers are explicitly supported under Linux: AMI Fast Disk VLB/EISA (BusLogic-compatible); Adaptec AVA-1505/1515 (ISA) (Adaptec 152x-compatible); Adaptec AHA-1510/152x (ISA) (AIC-6260/6360); Adaptec AHA-154x (ISA) (all models); Adaptec AHA-174x (EISA) (in enhanced mode); Adaptec AHA-274x (EISA)/284x (VLB) (AIC-7770); Adaptec AHA-2940/3940 (PCI) (AIC-7870); Always IN2000; BusLogic (ISA/EISA/VLB/PCI) (all models); DPT PM2001, PM2012A (EATA-PIO); DPT Smartcache (EATA-DMA) (ISA/EISA/PCI) (all models); DTC 329x (EISA) (Adaptec 154x-compatible); Future Domain TMC-16x0, TMC-3260 (PCI); Future Domain TMC-8xx, TMC-950; Media Vision Pro Audio Spectrum 16 SCSI (ISA); NCR 5380 generic cards; NCR 53c400 (Trantor T130B) (use generic NCR 5380 SCSI support); NCR 53c406a (Acculogic ISApport/Media Vision Premium 3D SCSI); NCR 53c7x0, 53c8x0 (PCI); Qlogic/Control Concepts SCSI/IDE (FAS408) (ISA/VLB); Seagate ST-01/ST-02 (ISA); SoundBlaster 16 SCSI-2 (Adaptec 152x compatible) (ISA); Trantor T128/T128F/T228 (ISA); UltraStor 14F (ISA), 24F (EISA), 34F (VLB); and Western Digital WD7000 SCSI.

In addition, there are some SCSI controllers that can be used under Linux only after patches have been added to an installed system. These controllers and the Internet locations of the patches are listed in Table 1.2.

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NOTE:  Parallel-port SCSI adapters (popular among laptop users) and DTC boards (327x, 328x) that are not Adaptec-compatible are not supported by Linux.

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The SCSI device must support block sizes of 256, 512, or 1024 bytes. Other block sizes will not work. (Use the MODE SELECT SCSI command to change the block size.)

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NOTE:  If you’re having trouble with SCSI and Linux, you’ll want to read the SCSI-HOWTO on the CD-ROM. See Appendix A for more details on this resource.

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However, be warned that you may need to play around with various SCSI cards, as you’ll see from this excerpt from the Slackware FAQ:

Q: Why the $%#@! isn’t my UltraStor SCSI detected? It works under DOS!

A: Set the I/O address to 0x340 instead to 0x330.

For any hardware that doesn’t work, a good rule is to try playing around with the IRQ and I/O settings on it to see what happens. If your system is up and running and you’re having problems with a CD-ROM or tape or something like this, you can always look around for the driver source in /usr/src/linux/drivers… really, it won’t bite! Often, the source contains important documentation, such as the default IRQ settings for that type of device and the major number for the entry in /dev. Also, try other boot kernels and see if that helps.

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NOTE:  A discussion of IRQs and interrupts can be found later in this chapter.

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Support for SCSI should extend to tape drives (as you’ll learn in the section entitled “Tape Drives,” later in this chapter).

Floppy Drive

The Linux installation process assumes that you’ll be creating a bootdisk and a rootdisk for use on a high-density drive. Because larger 1.2MB drives have all but disappeared from daily use, the accompanying CD-ROM contains drivers only for the 1.44MB, 3.5-inch floppies that most computers use for drive A:.

Tape Drives

Any tape drive that works from the SCSI connector, such as the QIC-20, should be fine under Linux (in other words, if your SCSI card works, so should the tape drive). In these cases, you’ll need to make sure that drives of both fixed and variable lengths have blocks smaller than the driver buffer length (set to 32k in the distribution sources). In addition, Linux works pretty well with other tape drives that are connected via floppy controller, like QIC-117, QIC-40/80, and QIC-3010/3020 (QIC-WIDE) drives.

Other tape drives using the floppy controller, including Colorado FC-10/FC-20, Mountain Mach-2, and Iomega Tape Controller II, should work, but you may have to grab a patch from ftp://sunsite.unc.edu/ pub/Linux/ kernel/tapes.

There are several unsupported tape drives, including Emerald and Tecmar QIC-02 tape controller cards, drives that connect to the parallel port (like the Colorado Trakker), some high-speed tape controllers (Colorado TC-15), the Irwin AX250L/Accutrak 250 (which are not QIC-80 compatible), the IBM Internal Tape Backup Unit (which is not QIC-80 compatible), and the COREtape Light.

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ON THE CD-ROMS:  For further information, check out FTAPE-HOWTO.

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