Peripheral device interface for dynamically selecting boot disk device driver

• US 5,430,845 A
• Filed: 06/17/1992
• Issued: 07/04/1995
• Est. Priority Date: 06/07/1990
• Status: Expired due to Term

• Current Assignee: Unisys Corporation
• Original Assignee: Unisys Corporation
• Inventors: Rimmer, Todd M., Jordan, William P.
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): DINH, DUNG C
• Application Number:
  US07/900,160
• Time in Patent Office: 1,112 Days
• Field of Search: 395/275, 395/475, 395/725, 395/700
• US Class Current: 710/12
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems

Abstract

A common peripheral device interface module is disclosed for use with the Unix (Unix is a trademark of AT&T) operating system which is flexible enough to support many types of disk or tape device drivers. A common disk module (CDM) is included. The CDM contains high level disk operation commands which may be used for common reference to each disk driver on the system. Routines within the CDM are accessed by the Unix system call interface through a series of operating system entry points. Additional routines are included with the pre-existing Unix operating system Disk I/O Subsystem to improve interfacing between this subsystem and the CDM. A common tape module (CTM) is used to perform high level tape operation routines. The Unix system call interface communicates with the CTM through a group of operating system entry points. Because there is no Unix operating system tape I/O subsystem, the CTM completely implements a tape I/O subsystem. To provide hardware portability, the CTM is configured to call a group of low level routines which have been incorporated into a device driver. Because of the large number of possible root disk device drives, the root disk device driver can be dynamically selected for the Unix operating system. Each controller which is resident within the system checks in with the operating system. The controller which checks in first with the operating system is used for booting up the system. Each controller which checks in is matched with an appropriate device driver. The matched device drivers are then used for disk I/O functions.

Claims

1. In a computer system including storage means and including a memory in which a plurality of program images are stored, swapped out and transferred to said storage means, apparatus for dynamically selecting a boot disk device driver for a Unix operating system from among a plurality of disk device drivers, comprising:

a. first indication means for determining if each of said plurality of disk device drivers is coupled to a respective one of a plurality of disk drive controllers;

b. second indication means for determining presence of at least one of a plurality of disk drives wherein each of said plurality of disk drives are coupled to a respective one of said plurality of disk device drivers;

c. transfer means, responsive to at least one of said first and second indication means, for transferring to the Unix operating system a value which uniquely identifies one of said plurality of disk drive controllers as said boot disk drive controller if a disk drive of said plurality of disk drives which is coupled to said one of said plurality of disk drive controllers has a root disk number;

d. means for a) coupling said boot disk drive controller to a corresponding device driver b) configuring said corresponding device driver as said boot disk device driver for booting said computer system; and

c) indicating to said computer system that said corresponding device driver is used for transferring to said storage means ones of said plurality of images swapped out of said memory.

2. The apparatus of claim 1, wherein said boot disk drive controller is the first of said plurality of disk drive controllers to indicate a presence.

3. The apparatus of claim 1, wherein said computer system includes means for indicating a presence of each of said plurality of disk drive controllers.

4. Apparatus for dynamically selecting a boot disk device driver according to claim 1, further comprising means for indicating to said computer system that said corresponding device driver is used for communicating with said storage means to receive from said storage means a respective numerical value corresponding to a respective one of said plurality of disk drives.

5. Apparatus for dynamically selecting a boot disk device driver according to claim 1, further comprising means for indicating to said computer system that said corresponding device driver is used for communicating with said storage means to receive from said storage means operating system program images.

6. Apparatus for transferring a first input/output (I/O) request between a Unix operating system and a first peripheral device controller coupled to a first I/O device and for transferring a second I/O request between said Unix operating system and a second peripheral device controller coupled to a second I/O device, each Of said first I/O request and said second I/O request one of a read request and a write request, said apparatus comprising:

a. Unix system call interface means for receiving said first I/O request and said second I/O request;

b. common device module means including a) common write means for writing data to either one of said first peripheral device controller and said second peripheral device controller and b) common read means for reading data from either one of said first peripheral device controller and said second peripheral device controller.

c. first and second operating system interface means, coupled to said Unix system call interface means, for receiving the first I/O request and the second I/O request, respectively, and for mapping each of the first I/O request and the second I/O request to one of said common read means and said common write means; and

d. first and second device driver means, coupled to said first peripheral device controller and said second peripheral device controller respectively, for transferring said first I/O request between either one of said common write means and said common read means and said first peripheral device controller and for transferring said second I/O request between either one of said common write means and said common read means and said second peripheral device controller.

7. The apparatus of claim 6, wherein details of said first I/O request determined by the operating system are implemented substantially exclusively in said common device module means.

8. The apparatus of claim 6, wherein the first device driver means and said first peripheral device controller are coupled to a first type of peripheral device, said apparatus further including:

a further peripheral device controller coupled to a second type of peripheral device;

further device driver means, coupled to said further peripheral device controller, including means for providing commands and data to said further peripheral device controller and means for receiving data from said further peripheral device controller;

wherein said common device module means includes means for conditioning said further device driver means to communicate with said further peripheral device controller.

9. The apparatus of claim 6, wherein said first peripheral device controller is a disk drive controller.

10. The apparatus of claim 9, wherein said first device driver means includes a disk I/O subsystem of a Unix operating system.

11. The apparatus of claim 10, wherein details of any interface requirements with the disk I/O subsystem of the Unix operating system are implemented substantially exclusively in said common device module means.

12. The apparatus of claim 9, wherein said common device module means transfers status information between the Unix system call interface means and the first device driver means.

13. The apparatus of claim 9, wherein said first device driver means comprises:

a. interrupt means for indicating that an I/O operation has been completed;

b. strategy means for initiating the I/O operation; and

c. printing means for providing diagnostic error messages.

14. The apparatus of claim 6, wherein said first peripheral device controller is a tape drive controller.

15. The apparatus of claim 14, wherein said first device driver means includes first and second sets of I/O command routines, coupled respectively to said Unix system call interface means and to said first peripheral device controller, and the common device module means is configured to transfer status information between said first and second sets of I/O routines.

16. The apparatus of claim 15, further including buffering means, coupled to said common device module means, for receiving a predetermined amount of data provided by said second set of command routines and for providing only such data as is requested through said Unix system call interface to said first set of command routines.

17. The apparatus of claim 6, further including means, coupled to said first device driver means, for receiving a signal from said first device driver means and for indicating to said Unix System Call interface means responsive to said signal that said first I/O device is ready to perform said first I/O request.

18. The apparatus of claim 6, wherein said common write means and said common read means are for writing to and reading from a disk unit, respectively.

19. The apparatus of claim 6, wherein said first device driver means is for transferring said first I/O request to said first peripheral device in a block oriented manner.

20. Apparatus for communicating with a plurality of peripheral devices in a computer system, comprising:

a. Unix system call interface means, for allowing a user to request a plurality of input/output (I/O) operations;

b. device driver means, including means for implementing first and second peripheral operation commands for use in communicating with said Unix system call interface means and said plurality of peripheral devices, respectively;

c. interface selection means, for mapping the user requested I/O operations between the Unix system call interface and the first peripheral operation commands of said device driver means; and

d. common device module means coupled to said device driver means for, from a common I/O routine included in said colon device module means, signaling said device driver means to sequence said second peripheral operation commands in a manner to perform operations represented by said first peripheral operation commands to access more than one of said plurality of peripheral devices.

21. The apparatus of claim 20, wherein said plurality of peripheral devices includes a disk drive.

22. The apparatus of claim 20, wherein said plurality of peripheral devices includes a tape drive.

23. The apparatus of claim 20, further including means, coupled to said device driver means, for receiving a signal from said device driver means and for indicating to said Unix System Call interface means responsive to said signal that one of said plurality of peripheral devices is ready to perform one of said plurality of requested I/O operations.

24. The apparatus of claim 20, wherein one of said plurality of peripheral devices is a disk unit and said I/O routine is for communicating with said disk unit.

25. The apparatus of claim 24, wherein said I/O routine is for communicating with said disk unit in a block oriented manner.