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Devices and Drivers.

5 Devices and Drivers.

5.1 What are they?

Here is an example of the contents of the /dev directory.

5.2 Description of SCSI.

The Small Computer System Interface (pronounced "scuzzy") specification was developed to allow up to 7 devices to be intelligently controlled by each interface rather than the computer. SCSI adapters are common on most workstations today as part of the motherboard.

5.3 Disk Special File Names (standard /usr partition)

Table 3: Disk Special File Names 
                 BSD           System V.4        SunOS 4.1.3  IRIX                
File Name        /dev/rdisk0g  /dev/rdsk/c1d0s2  /dev/rsd0g   /dev/rdsk/dks0d0s2  
Raw access mode  /dev/rdisk0g  /dev/rdsk/c1d0s2  /dev/rsd0g   /dev/rdsk/dks0d0s2  
Device Type      /dev/rdisk0g  /dev/rdsk/c1d0s2  /dev/rsd0g   /dev/rdsk/dks0d0s2  
Drive #          /dev/rdisk0g  /dev/rdsk/c1d0s2  /dev/rsd0g   /dev/rdsk/dks0d0s2  
Disk Partition   /dev/rdisk0g  /dev/rdsk/c1d0s2  /dev/rsd0g   /dev/rdsk/dks0d0s2  
Controller #                   /dev/rdsk/c1d0s2               /dev/rdsk/dks0d0s2  
OSF/1 (Digital Unix) and Digital Ultrix look similar to BSD style, while SunOS 5.x uses System V.4 style device files but also provides BSD style device names via use of symbolic links (for backward compatibility with SunOS 4.x).

5.3.1 Particular naming schemes for SCSI discs

5.4 Common "tricks" with devices.

5.5 Example: Adding a tape drive to a Digital Unix system

N = (8 * SCSI bus #) + SCSI target #
= (8 * 0) + 5
= 5
# cd /dev
# ./MAKEDEV tz5
MAKEDEV: special file(s) for tz5: 

5.6 Example Problems

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