GB2246649A

GB2246649A - Computer error code diagnostic apparatus and method

Info

Publication number: GB2246649A
Application number: GB9016988A
Authority: GB
Inventors: Michael William Houghton
Original assignee: GRANADA COMPUTER SERVICES
Current assignee: GRANADA COMPUTER SERVICES
Priority date: 1990-08-02
Filing date: 1990-08-02
Publication date: 1992-02-05
Anticipated expiration: 2010-08-02
Also published as: GB2246649B; GB9016988D0

Abstract

Diagnostic apparatus for peripheral connection to a computer 10 for storing and analysing transient error codes generated by the computer, comprises an interface module 16, adapted for connection to a data bus 12 of the computer through which the error codes are transmitted in use, for latching successive error codes; and data-processing means 18 connected to receive the latched error codes from the interface module and having a buffer memory for storing the error codes, means for interpreting at least selected error codes and converting them into error message text, means 19 for displaying selected error codes or the associated text, and operator controls 20 including means for selecting the error codes from those stored in the buffer memory. <IMAGE>

Description

COMPUTER ERROR CODE DIAGNOSTIC APPARATUS AND METHOD This invention relates to diagnostic apparatus, and an associated method, for the analysis of transient error codes, for example boot codes, generated by a computer, for example a mainframe computer.

A mainframe computer, such as the ICL System 39, may have no console as such, the operator controlling the system by way of a video display unit or a keyboard printer. As the computer is powered up, and its operating system is loaded (booted), various messages are generated in sequence, and are usually displayed transiently in the form of hexadecimal numerals on a display panel. If the power up sequence (boot) is entirely successful, then the only message shown may for example be the time of day. If there is an error or multiple errors, then an error code or codes will be displayed. Information relating to the power supply may also be displayed. Such error codes and power supply codes are known collectively as boot codes.

The boot codes are generated on a data bus forming part of the mainframe computer; they may be displayed either on a panel on the computer itself, or else on a remote device connected to the computer by way of a communications link, for example a fibre optic link.

Some of the boot codes are displayed for long enough to enable them to be noted by an operator, but others flash by very quickly, to be replaced by subsequent codes.

The purpose of the invention is to overcome the problems associated with the transience of such messages.

Accordingly, the invention provides diagnostic apparatus for peripheral connection to a computer for storing and analysing transient error codes generated by the computer, comprising: an interface module, adapted for connection to a data bus of the computer through which the error codes are transmitted in use, for latching successive error codes; and data processing means connected to receive the latched error codes from the interface module and having a buffer memory for storing the error codes, means for interpreting at least selected error codes and converting them into error message text, display means for displaying selected error codes or the associated text, and operator controls including means for selecting the error codes from those stored in the buffer memory.The interface module is preferably connected directly to the computer, but may instead be connected thereto by way of a communications link.

It is anticipated that the error codes will principally be boot codes or parts thereof, generated during the power up sequence of the computer, which would normally be a mainframe computer although the invention could be used with other types of computer.

The apparatus preferably includes a cable carrying data and control lines, linking the data-processing means with the interface module. This cable preferably also comprises a power line enabling the data processing means to draw power from the computer.

The interface module is preferably adapted for connection to the said data bus in parallel with an error code display device forming part of the computer, the diagnostic apparatus being transparent to the computer.

The operator controls preferably comprise means for allowing the scanning of the stored error codes and/or the associated text in relation to the sequence in which the codes were generated by the computer. The controls preferably form part of a unit with the buffer memory and the interpreting means, but this is not essential, and for some applications it is more convenient that the operator controls (and preferably also the display means) are remote from the remainder of the data processing means, and are linked thereto by a communications link. Alternatively, the remote control system could be provided in addition to the controls on the unit itself, for intermittent remote operation as and when required.

The invention also provides a method of monitoring the status of a computer which generates transient error codes, comprising latching successive error codes, storing them in a buffer memory, responding to operator selection to identify at least one of the stored error codes, interpreting at least the selected stored error code and converting it into error message text, and responding to operator selection to display the error code or the associated message text.

With the diagnostic apparatus or the monitoring method as described, the display of the error code or the associated error message text may be on a display panel or screen such as a liquid crystal display, but may alternatively be constituted by a printer generating a printed output.

A preferred form of the invention will now be described, by way of example only, with reference to the accompanying drawing which is a diagrammatic illustration of diagnostic apparatus embodying the invention connected to part of a mainframe computer.

A mainframe computer 10, for example the ICL System 39, includes a panel 13 of hexadecimal displays, connected in a data bus 12, 14. The codes displayed on the panel are known as "footprints|. During the power up sequence, the hex display panel 13 displays two hex numerals, indicative of power supply status, and six hex numerals, representing one of a sequence of error codes.

In the absence of any error during power up, however, the panel 13 simply displays the time of day.

The diagnostic apparatus embodying the invention includes an interface module 16 connected by way of hook-up ribbons 15 in parallel with the hex display panel 13, so that it is entirely transparent to the mainframe computer. The interface module 16 contains logic circuitry to latch and hold the information displayed on the hex display panel 13, i.e. binary codes representative of hexadecimal numerals. In this example, the interface module 16 is programmed to ignore the two hexadecimal numerals representative of power supply codes, and to store only the six hexadecimal numerals representative of error codes.

The interface module includes a ribbon cable 17 which connects the mainframe computer to a main tester unit 18. The cable carries data, control and power lines. A standard driver interface connects the interface module 16 to the cable 17, whose other end is connected to a standard buffer chip in the tester unit 18. In this example, the main tester unit 18 draws its very low power from the mainframe computer 10, but in alternative forms of the invention the tester 18 has its own internal power source or a cable for connection to an external power supply.

The main tester unit 18 consists of a microprocessor system with an external control panel 20, a liquid crystal display unit 19 and an RS 232 communications card and port 27 for optional remote control by way of a communications line, over-riding the LCD display 19 and operator control panel 20. In this example, the RS232 link allows remote dial up for monitoring purposes, or to download tester data, to make hard copy, or to create disk files of such data. This link is normally dormant, but wakes up upon access. Upon exit from such remote access, the tester resumes its function and the communications link sleeps.

The microprocessor system has hardware which includes up to 127 32k eproms (erasable programmable read only memories) which together occupy only a single 16k address space. This allows a theoretical space of over 4 Mb of text in a simple eight bit/64k system. A software routine to compress the text increases this capacity by about a third. This read only memory stores the error message text associated with each error code which may be generated by the computer 10, and is addressable by the microprocessor operating system when it executes a program for interpreting one or more of a sequence of error codes which have been latched in the interface module 16 and transmitted to the tester unit 18.

The LCD display 19 has a field for displaying the footprint or successive footprints in the form of six hexadecimal numerals, and a separate field for displaying the associated text. Preferably, the display 19 also displays an acknowledgement of instructions entered on an operator keyboard 20, and messages from a help file stored in the microprocessor memory.

The error message data from the interface module 16 is stored in a RAM (random access memory) buffer memory (not shown), which has a capacity of 2,600 footprints.

When the memory is full, it ceases to trap footprints, and the microprocessor control then enters an edit mode which allows the operator to scan through the buffer memory to select for interpretation any footprint desired. Alternatively, a switch on the front panel keyboard 20 can be set such that when the buffer memory fills, it is cleared and the loading process is restarted, thus ensuring that the last 2,600 footprints are always available. (Although not shown in this example, a printer may be included intergrally in the tester unit 18, to provide a hard copy of the information provided).

The operator control keyboard 20 comprises three sets 21, 22 and 23 to 26 of control keys. Each key has a built-in L. E. D. indicating, when on, that the function it indicates is switched on or is operative. The first group 21 comprises four scrolling keys 21a to 21d for scrolling the footprints displayed on the LCD display 19, vertically or horizontally in either direction.

This enables the operator to scan rapidly the stored sequence of footprints, by appropriate random access of the RAM buffer memory. A cursor on the display points to the footprint which is to be selected for decoding.

A second group 22 of control keys comprises a "halt" key 22a, for stopping the tester from buffering codes and allowing data to be reviewed, in a review mode, and a "shift key 22b for fast scrolling of the LCD screen on the display 19. The third group of keys comprises two special function keys F1 and F2 for use in the review mode. Key F1 provides HELP text displayed on the display 19. Key F2 causes entry into a manual input mode in which footprints are input manually and are decoded, using the tester in effect as a directory.

Two reset keys 23, 24 perform a reset of the data processor within the tester unit. The right-hand reset key 24 is capable of being latched on, in which case the buffer memory automatically clears and restarts upon filling, thus storing only the most recent 2600 footprints. Otherwise, the tester automatically exits to the review mode as soon as the buffer memory has filled.

In the event of a communications error, the L. E. D. 5 on the keys are illuminated in a combination such as to indicate the error status, to enable fault finding, and so forth. Disconnection of the communications line from port 27 provides a reset facility.

The main tester unit 18 may also be used independently of the mainframe computer 10, and in this case an independent power supply is essential. In this remote mode of operation, the message text associated with a particular error code may be obtained by scanning tie full directory of stored error codes until the selected code is located, and then displaying the associated error message text as obtained from the read only memory.

Where the tester unit 18 is capable of being powered either from the mains or from the mainframe computer 10, circuitry is included to prevent power being supplied in the wrong direction to the mainframe computer.

Claims

1. Diagnostic apparatus for peripheral connection to a computer for storing and analysing transient error codes generated by the computer, comprising: an interface module, adapted for connection to a data bus of the computer through which the error codes are transmitted in use, for latching successive error codes; and data-processing means connected to receive the latched error codes from the interface module and having a buffer memory for storing the error codes, means for interpreting at least selected error codes and converting them into error message text, display means for displaying selected error codes or the associated text, and operator controls including means for selecting the error codes from those stored in the buffer memory.

2. Diagnostic apparatus according to Claim 1, in which the error codes are boot codes (or parts thereof) generated during the power up sequence of the computer.

3. Diagnostic apparatus according to Claim 1 or 2, comprising a cable carrying data and control lines, linking the data-processing means with the interface module.

4. Diagnostic apparatus according to Claim 3, in which the cable comprises a power line enabling the data-processing means to draw power from the computer.

5. Diagnostic apparatus according to any preceding claim, in which the interface module is adapted for connection to the said data bus in parallel with an error code display device forming part of the computer, the diagnostic apparatus being transparent to the computer.

6. Diagnostic apparatus according to any preceding claim, in which the operator controls comprise means for allowing the scanning of the stored error codes and/or the associated text in relation to the sequence in which the codes were generated by the computer.

7. Diagnostic apparatus according to any preceding claim, in which the operator controls are remote from the remainder of the data-processing means, and are linked thereto by a communications link.

8. A mainframe computer having an error code display connected to a transient error code source, connected to diagnostic apparatus in accordance with any preceding claim.

9. A method of monitoring the status of a computer which generates transient error codes, comprising latching successive error codes, storing them in a buffer memory, responding to operator selection to identify at least one of the stored error codes, interpreting at least the selected stored error code and converting it into error message text, and responding to operator selection to display the error code or the associated message text.

10. A method according to Claim 9, in which the error codes are boot codes (or parts thereof) generated during the power up sequence on the computer.

11. A method according to Claim 9 or 10, including responding to operator selection to scan the stored error codes and/or the associated text in relation to the sequence in which the codes were generated by the computer.

12. Apparatus for storing and analysing boot codes, substantially as described herein with reference to the accompanying drawing.

13. A method of storing and analysing boot codes, substantially as described herein with reference to the accompanying drawing.