US 5,598,577 AGrant
Computer System With Automatic Drive Model ID Recognition and Drive Type Adaptation
Issue Date:1997-01-28
•20 Claims
•8 Drawing Sheets
Abstract
A computer system in which the system software (while running as an overhead process which is not directly under control of the user) queries a disk drive to determine its model. The system software checks the corresponding response string with reference to a table of recognized model strings (in encrypted format). If the drive's response string is recognized in this table, then the drive parameters can be set appropriately. If not, then this portion of the system software will not set the drive parameters; instead, the normal manual setup procedure can be used.
Metadata
Assignee
- Dell USA, L.P.
Inventor
- Anthony L. Overfield
Application Information
Application Number:US 5693098
Filing Date:1995-12-08
Priority Date:1991-12-26
Art Unit:236
Classifications
IPC:
G06F 1310G06F 900
Field of Search:
395364700;427;428;442;497.01;833;828;830243;964
Patent Drawings (8 sheets)
Description
All of the material in this patent application is subject to copyright protection under the copyright laws of the United States and of other countries. As of the first effective filing date of the present application, this material is protected as unpublished material.
Portions of the material in the specification and drawings of this patent application are also subject to protection under the maskwork registration laws of the United States and of other countries.
However, permission to copy this material is hereby granted to the extent that the owner of the copyright and maskwork rights has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure, as it appears in the United States Patent and Trademark Office patent file or records, but otherwise reserves all copyright and maskwork rights whatsoever.
Background and Summary of the Invention
The present invention relates to small personal computers, and to methods for using them.
The innovations disclosed in the present application provide computer systems (especially very small portable personal computers) which have advantageous new capabilities for disk drive management. To better explain the significance and advantages of these innovations, the following paragraphs (down to page 5) will review some technological context. This technological context is not necessarily prior art, but is intended to help in pointing out the disclosed inventions.
Laptop and Smaller Computers
Portable personal computers were introduced in the early 1980s, and proved to be very useful and popular. As this market has developed, it has become increasingly dear that users strongly desire systems to have small volume, small weight, physical durability, and long battery-powered lifetime. Thus, small portable computers ("laptop" computers) have proven extremely popular during the late 1980s. Users continue to demand more features, longer time between recharges, and lower weight and volume. This combination of demands is difficult to meet. Moreover, as of 1990, another smaller generation of portable computers has begun to appear, referred to as "notebook" computers. This smaller form factor will only exacerbate the difficulty of the above tradeoffs.
Note that the hard drive in a notebook computer is normally bolted in, and is not intended to be readily changed by the user. Thus, since the choice of hard drives is controlled by the manufacturer, the system does not have as difficult a recognition problem as it would if users could freely introduce new hard drive modules.
Basic System Software
Whatever hardware is used will have its own procedures to return to a known state when a reset occurs. However, at some point these procedures end, and the CPU is ready to begin execution of instructions.
At this point the system performs various overhead tasks under software control. These may include surveying the system configuration, sanity checks, etc.
"Basic Input/Output System" Software (BIOS)
In modern personal computers, the initial target address is normally used as the entry point to a "basic input/output system" (BIOS) program. The BIOS program contains frequently-used routines for interfacing to key peripherals, for interrupt handling, and so forth..sup.1 In addition to these basic input/output routines, the "BIOS" software also includes some key pieces of overhead software, such as configuration update and the power-on-self-test (POST) routines..sup.2 The BIOS software will also launch the machine into the operating system software..sup.3 (Thus, the term "BIOS" has become somewhat broader nowadays, and normally refers to this whole collection of basic system routines.)
Disk Drive Management in Personal Computers
In standard personal computers, the operating system must be aware of a significant number of disk parameters, including the heads, cylinders, sectors, and interleave. See generally Rosch, "Sectors, tracks, and heads," PC SOURCES vol. 2 no. 1 (Jan. 1991), at 378, which is hereby incorporated by reference; and Roberts, "Finding disk parameters," PC TECH JOURNAL, vol. 4 no. 5 (May 1986), at 112ff, which is hereby incorporated by reference.
Normally, the user advises the system software of disk parameters, as follows:
When the computer is booted, it always offers the user the opportunity to branch into a SETUP utility. Also, if the computer detects corruption of the configuration memory data, or if the computer detects a mismatch between the configuration memory data and the installed equipment, or (sometimes) if a hardware error is encountered during the POST routines, the POST software will invite the user to enter the SETUP routine.
When the user runs the SETUP routine, it displays a table of numbered drive types, with parameters for each. The user is asked to select one of these drive types. (Recent SETUP routines will query the drive to ascertain its parameters, and will suggest a choice to the user.) After the user selects a drive type, the relevant information is stored in the configuration memories in nonvolatile memory (battery-backed CMOS), and the user is prompted to reboot the computer.
Selecting a drive type is confusing to new users, and presents some possibility for error. Consequences of such errors can easily include inoperability or loss of data, ff an inexperienced user gets into manual SETUP without realizing what he is doing.
The Integrated Drive Electronics (IDE) Disk Interface
In recent years, interfacing to hard disk drives has been greatly simplified by the rapid introduction of Integrated Drive Electronics (IDE) disk drives. An IDE drive includes the drive controller electronics integrated with the drive, so the interface to it can be a high-level digital interface. As drives have evolved, the interface is becoming standardized; this evolving interface is referred to as the AT Attachment interface, hereinafter "ATA" and has been proposed for adoption as an American National Standards Institute, hereinafter ANSI standard. See generally Alford, "The IDE Hard Disk Drive Interface," BYTE magazine, March 1991 (vol. 16 No.3), at 317ff, which is hereby incorporated by reference.
An IDE drive controller does handle many low-level tasks (such as soft error detect and retry), and some can even remap the drive sectors invisibly to the operating system; but (at least with current IDE interface definitions, and with current operating systems such as DOS, OS/2, and UNIX) the IDE controller does not fully mask the drive specifics from the operating system. Thus, the CPU, under control of the system software, still needs to be able to ascertain the drive parameters.
Under the evolving ATA standard, one of the commands which an IDE drive controller will recognize is an identity query. In response to such a query, the controller will output a block of data which includes the drive's model number and serial number, as well as parameters for the drive.
Computer System with Automatic Drive: Model ID Recognition and Adaptation
The present application discloses a computer system in which the system software (while running as an overhead process which is not directly under control of the user) queries a disk drive to determine its model. The disk drive returns a data field which includes an ID string, and the system software compares this string against a table of recognized model strings. If the drive's response string is recognized in this table, then the drive parameters can be set appropriately. If not, then this portion of the system software will not set the drive parameters. (However, the normal manual setup procedure can still be used.)
The presently preferred embodiment implements this idea in an ISA architecture. In this case the POST process (stored in the BIOS ROM) queries the hard disk to determine what kind it is and automatically sets the CMOS hard disk drive type to its corresponding value. Previously, this required knowing the CMOS drive type number of the hard disk, or knowing the correct drive parameters and searching through all available CMOS drive types to find the one that corresponds.
Limited Use of Drive's Self-Description Capability
When the CPU is running the innovative software, it issues an identification query to the drive: for example, with an IDE drive, the CPU issues an "IDE.sub.-- identify" command. In response to this command, an IDE drive will return a block of data (in a format substantially defined by the ATA standard) which includes a model-unique identification string. That is, this string will specify the manufacturer's model number (e.g. "Conner Peripherals 42MB--CP2044") at byte 36.sub.H of the block of 512 bytes.
The block of data returned by an IDE drive also includes drive parameters. However, the present invention does not use these drive parameters (except, optionally, as additional bits of input to the string match, as detailed below.
The disclosed innovative architecture also provides additional options for exploitation. Thus, for example, an IDE controller might be running an emulation, which could be bypassed by software according to the present inventions, if the IDE's emulation would not produce optimal efficiency for a particular application.
Encryption
Preferably the table of permissible model strings is stored in encrypted format. This prevents competitors from simply reading out the list of permissible drive models (which would disclose supplier information). In this case the comparison operation must be adapted accordingly.
In the presently preferred embodiment, the table of permissible model strings is encrypted using a very simple algorithm: the values are simply XORed with a constant. This provides some minimal impediment to competitors' inspection.
The string returned by the disk drive is tested with reference to the encrypted entries. (The comparison operation itself includes translation steps which permit the unencrypted returned string to be compared, without a separate transformation operation, to the encrypted entries in the table.)
Launch from POST
The innovative routine is called out of POST. It recognizes the drive. It looks up the optimal type number for that drive, and writes the nonvolatile configuration memory accordingly. However, if this routine does not recognize the drive model string, it changes nothing.
As part of the POST routines, the innovative procedures will run every time the computer is booted. However, these procedures do not add any significant delay to the boot process.
Sequence of POST Steps
The innovative drive-recognition steps are preferably performed before any disk-access operations are needed. Thus, in the presently preferred embodiment, these drive-recognition steps are performed just after the reset and self-test of the drive is initiated.
Updating
To obtain the maximum benefit, the table of hard drive models in the system software should be updated to recognize new drive models, before systems with the new drive model are released. Thus, in practice, the engineering team which evaluates a new drive for possible inclusion will add the additional recognition entry into the BIOS. By the time the new drive model is cleared for shipping, the corresponding recognition capability is already in the BIOS.
Currently there are ten different drive models in the recognition table, but of course this is expected to change.
Forward Compatibility.
The disclosed system and method provides improved forward compatibility. New drive models continue to be introduced, and there remains at least a theoretical possibility that a new drive model might match an existing model in some parameters, but not in all. Thus, recognition by parameter comparisons raises a risk of misrecognition.
Of course, as new drive models are introduced, the BIOS software can be updated accordingly.
Brief Description of the Drawing
The present invention will be described with reference to the accompanying drawings, which show important sample embodiments of the invention and which are incorporated in the specification hereof by reference, wherein:
FIG. 1 is a flow chart showing the general sequence of some of the key operations in the power-on-self-test (POST) operations of a sample microcomputer system, and shows the general point within POST where the innovative operations are preferably performed.
FIG. 2 is a flow chart showing the general sequence of the innovative drive-adaptation operations.
FIGS. 3A-3E show the detailed structure of the preferred hardware embodiment.
FIG. 4 shows the notebook computer of the presently preferred embodiment.
Description of the Preferred Embodiments
The numerous innovative teachings of the present application will be described with particular reference to the presently preferred embodiment. However, it should be understood that this class of embodiments provides only a few examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily delimit any of the various claimed inventions. Moreover, some statements may apply to some inventive features but not to others.
Sample Hardware Implementation
The presently preferred embodiment has been implemented on several different computer systems. The primary disclosed embodiment relates to the Dell 320N computer. This is a notebook computer, with an external closed size of about 8.5.times.11.times.2 inches.
FIG. 4 shows a perspective view of the notebook computer of the presently preferred embodiment in the open position. Visible elements include case 802, cover 804, hinges 806, display screen 810, keyboard 820, floppy disk drive 830, and battery door 803 (which covers the receptacle for the rechargeable battery pack).
The microprocessor 300 is an Intel 386SX processor running at 20 MHz. (Hardware details and options of this computer, in the presently preferred embodiment, are extensively described in readily available Dell product literature, which is hereby incorporated by reference.) However, this model is merely one example of the hardware environments in which the inventions have been demonstrated to work.
In the presently preferred embodiment, an HT21 chip 310, from Headland Technologies, is used to provide a variety of peripheral support functions to the main microprocessor. These include bus management, memory management, interrupt control, and DMA control. Serial port management and keyboard interface, and other I/O management functions, are provided by a VTI 82C106 combination chip 350. Of course, other implementations of support logic and glue logic can be used if desired, within this well-known architecture.
FIGS. 3A-3E show the detailed structure of the preferred hardware embodiment.
This computer is a notebook computer, which includes a compact keyboard and screen in a rugged plastic case with a battery power supply.
FIG. 3A gives an overview of the principal electronic components of hardware architecture.
Microprocessor 300, in the presently preferred embodiment, is a 386SX processor running at a 20 MHz clock rate. This microprocessor accesses bus 311, and memory 312, through controller 310. Bus and memory controller 310, in the presently preferred embodiment, is an HT21 chip from Headland Technologies. This chip provides a variety of peripheral support functions to the main microprocessor, including bus management, memory management, interrupt control, and DMA control.
Bus 311, in the presently preferred embodiment, is an ISA bus. Memory 312, in the presently preferred embodiment, is DRAM, as discussed below.
Video controller 330 is, in the presently preferred embodiment, a VGA chip, and is connected to additional components as shown in FIG. 3C below. This is implemented as a WD 90C20 VGA controller chip, in the presently preferred embodiment; but of course other components can optionally be used instead.
Power Management Controller 320 is a microcontroller, in the presently preferred embodiment, and is connected to additional components as shown in FIG. 3D below.
Hard disk drive 340, in the presently preferred embodiment, is a ruggedized 21/2" IDE drive, such as the Conners Peripherals CP2044 42MB 2.5" hard disk. (Other sizes are also available.)
Serial port management and keyboard interface, and other I/O management functions, are provided, in the presently preferred embodiment, by a VTI 82C106 combination chip 350. (Of course, other implementations of support logic and glue logic can be used if desired, within this well-known architecture.) Combination I/O Controller 350 is connected to additional components as shown in FIG. 3E below.
FIG. 3B shows additional details of the connections of microprocessor 300 and bus controller 310. The microprocessor 300 is connected in parallel with a socket for an optional numeric co-processor 302 (e.g. a 387SX chip). Bus controller 310 receives two oscillator inputs. A 40 MHz crystal-controlled oscillator 319 provides a signal which is divided down to provide the dock for microprocessor 300. A 32 MHz crystal-controlled oscillator 318 provides a signal which is divided down to provide the clock for bus 311.
The standard component of memory 312 is one megabyte of DRAMs, 8 bits wide. Sockets are provided for optional expansion memory 314 (1M.times.8 or 2M.times.8), and for optional expansion memory 316 (2M.times.8). Both of these optional expansion memories are connected in parallel with memory 312 (except for slightly different address line connections).
Flash EEPROM 360 provides a rewritable boot memory. (The operation of this memory is described in detail in commonly owned application 707,121, filed May 29, 1991, entitled "Computer System with Restorable Basic Firmware" (DC-200), which is hereby incorporated by reference.) When the flash memory 360 must be programmed, DC-DC converter 362 generates a 12-Volt programming voltage from the 5-Volt supply.
The hardware system of the presently preferred embodiment uses only three circuit boards for all components other than the external power supply. The components shown in FIGS. 3B and 3E are included on a common circuit board. However, FIGS. 3C and 3D show components which are on an I/O (bottom) circuit board 321 or inside the screen housing 333.
FIG. 3C shows additional details of the connections of the video controller 330. A 14.318 MHz crystal-controlled oscillator 331 provides a reference frequency to video controller 330 and to bus controller 310. The video controller provides video output to inverter 334 and LCD display panel 336. (This is a Sharp VGA flat panel display, in the presently preferred embodiment, but of course other displays can be substituted.) A connection is also provided, in the presently preferred embodiment, for an external CRT monitor 332, which, if connected, can also be supplied with video signals from video controller 330.
FIG. 3D shows additional details of the connections of the power management microcontroller 320. In the presently preferred embodiment, this is a National Semiconductor COP888CF series microcontroller, which is connected to receive various inputs for power-monitoring. An ASIC 322 provides interface logic, including sequential logic, for interfacing the microcontroller 320 to the system bus 311. An 8 MHz crystal-controlled oscillator 323 provides a clock signal to microcontroller 320 and interface chip 322. An SRAM 324 (which may be 8K.times.8 or 32K.times.8) is also accessed through the interface chip 322. This provides local memory which the microcontroller 320 can use. U.S. patent application 07/655,889, filed Feb. 14, 1991 and entitled "Portable Computer with BIOS-independent Power Management" (DC-172), provides extensive detail concerning power management microcontroller 320 and ASIC 322. This application is hereby incorporated by reference.
FIG. 3E shows additional details of the connections of the combination I/O controller 350. This chip receives dock inputs from an 18.432 MHz crystal-controlled oscillator 351B, and from a 32 KHz crystal-controlled oscillator 351A. This chip, in the presently preferred embodiment, is a VTI 106; but of course a variety of other combination I/O management chips are available from Headland, Chips & Technologies, and other vendors, and other such chips can optionally be designed in.
I/O controller 350 is connected to receive input from mouse port 386.
I/O controller 350 is also connected to receive input from built-in keyboard 380, or from an external keyboard when one is plugged into external keyboard port 384.
I/O controller 350 is also connected to communicate with an internal modem 354, if one is installed.
I/O controller 350 is also connected to communicate, through RS232 interface 352, with a serial port connector (not shown).
I/O controller 350 is also connected to communicate, through multiplexer 374, with printer (parallel) port 390. Note that multiplexer 374 also, in the presently preferred embodiment, permits the floppy disk controller 372 to send and receive floppy disk interface signals over the parallel port connector 390. This novel feature permits an external floppy drive to be connected to the printer port connector 390.
Floppy disk controller 372 interfaces to bus 311, and receives a clock signal from 24 MHz oscillator 371. Floppy disk controller 372 is a standard controller for a 31/2" floppy disk drive 370, which, in the presently preferred embodiment, is an Epson 3.5" floppy disk drive unit.
Encryption
The table of permissible model strings, in the presently preferred embodiment, is stored in encrypted format. In the presently preferred embodiment, a very simple encryption is used: the values are simply XORed with a constant (SA.sub.H in the presently preferred embodiment). Alternatively, a more complex encryption scheme can be used if desired; but even this provides some minimal impediment to competitors' inspection.
Software Implementation Details
Following is a sample specific implementation of software portions of the disclosed innovations. This example is intended to better illustrate the disclosed generally applicable innovations, and to comply with the best-mode requirements of U.S. patent law; but of course this specific implementation is subject to change (and will certainly be changed as time goes by), and can be altered, as will be apparent to those skilled in the art, in many details.
The code portions set forth below provide the most relevant portions of the code used, but of course these code portions are used in combination with large additional portions of code. In the presently preferred embodiment, the software structure given below is used in combination with Phoenix.TM. BIOS code; but several vendors (such as AMI) offer BIOS software, and the disclosed code can be used with another vendor's BIOS code if desired. (Of course, minor adjustments would have to be made to the called routine names, etc.)
Encryption-Related Macros
The following macros hide the hard drive strings from casual
Note that a zero is used to mark the end of the string.
Further Modifications and Variations
It will be recognized by those skilled in the art that the innovative concepts disclosed in the present application can be applied in a wide variety of contexts. Moreover, the preferred implementation can be modified in a tremendous variety of ways. Accordingly, it should be understood that the modifications and variations suggested below and above are merely illustrative. These examples may help to show some of the scope of the inventive concepts, but these examples do not nearly exhaust the full scope of variations in the disclosed novel concepts.
The preferred embodiment is primarily directed toward an "AT-compatible" architecture, in which the disclosed inventions are advantageously applied to getting the correct value into the configuration memory. While the disclosed innovations are particularly advantageous in such a context, they can also be adapted to quite different architectures. For example, the disclosed innovations can be used in any other computer which uses IDE drives (e.g. in a workstation).
In addition, it should be noted that the disclosed innovations are not limited to use with the ATA interface, and are not necessarily limited to use with IDE drives. The disclosed innovations can also be applied to other drive controllers which provide a drive-specific self-identifying string in response to an identity query. (For example, some ESDI controllers have the capability to return a controller-specific self-identifying string; and at least some of the disclosed innovations may be adaptable to other controllers with a Western-Digital-type interface.
It should be noted that, although the presently preferred embodiment launches the drive-recognition procedure out of POST, the innovative steps could optionally be commenced in other ways (for example, as part of the initialization of a device driver).
In an alternative embodiment, the table format and string compare operation are modified to compare not only the drive model ID, but also the other parameters returned by the drive. This alternative embodiment helps to ensure against the risk that a manufacturer might change drive parameters without changing the drive model number. Of course, the serial number field is preferably omitted from this comparison, since it is different for each individual drive.
In a further contemplated alternative embodiment, additional comparisons can be done on the serial number field. However, this alternative is not preferred, since manufacturers tend to be somewhat inconsistent in the progression of their serial numbers.
In the present embodiment, the normal SETUP routine in the BIOS ROM remains available, in case the described software is unable to recognize the drive, so that the user can still call the SETUP utility to set the drive type manually. But this ability can be removed in an alternative embodiment.
As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a tremendous range of applications, and accordingly the scope of patented subject matter is not limited by any of the specific exemplary teachings given.
Claims
What is claimed is:
1. In a computer system having a disk drive and having a configuration memory, a method of conditionally specifying to the computer system a plurality of drive parameters appropriate for the disk drive, comprising the steps of: sending a model-identification-query to the disk drive, said model-identification-query causing the disk drive to return a model-identification-string which identifies the disk drive's manufacturer and model number: comparing the model-identification-string returned from the disk drive against a plurality of entries within a recognition table, said recognition table containing an entry for each of a plurality of disk drives, by vendor and model number thereof, which are each known to perform satisfactorily with the computer system, said recognition table being pre-stored within the computer system and containing, for each entry, a field specifying a permissible model-identification-string for the respective entry and a field specifying a corresponding drive-type-number for the respective entry, said comparing step for finding an entry within the recognition table which corresponds to the returned model-identification-string, if such a matching entry is present within the recognition table, and otherwise for determining that no matching entry is present within the recognition table; retrieving, upon finding a matching entry within the recognition table, the drive-type-number corresponding thereto; storing, upon retrieving a drive-type-number from the recognition table, the retrieved drive-type-number into the configuration memory of the computer system; and preventing upon determining that no matching entry is present within the recognition table, a user of the computer system from manually storing a drive-type-number into the configuration memory of the computer system; wherein the drive parameters appropriate for the disk drive are specified to the computer system by reference to a pre-stored configuration table using the retrieved drive-type-number previously stored within the configuration memory, said configuration table containing, for each drive-type-number from a group of known drive-type-numbers, a corresponding plurality of drive parameters.
2. A method as in claim 1 wherein the comparing step comprises the steps of: encrypting the model-identification-string returned from the disk drive, thereby forming an encrypted returned model-identification-string; comparing the encrypted returned model-identification-string against entries within the recognition table until a matching entry is found, if at all, said entries within the recognition table containing permissible model-identification-strings which are pre-encrypted in like manner as in the encrypting step; thereby preventing the direct reading of permissible model-identification-strings within the recognition table unless the encrypting step is known.
3. A method as in claim 1, wherein the model-identification-string returned from the disk drive includes a plurality of drive parameters appropriate for the disk drive; and wherein each of the plurality of permissible model-identification-strings stored within the recognition table includes a plurality of drive parameters appropriate for a disk drive corresponding to the respective entry; and wherein the comparing step finds a matching entry within the recognition table only if the plurality of drive parameters contained within the returned model-identification-string matches an entry within the recognition table.
4. A method as in claim 2 wherein the encrypting step comprises the step of performing, for each byte of the returned model-identification-string, a byte-flip operation.
5. A method as in claim 2 wherein the encrypting step comprises the step of performing, for each byte of the returned model-identification-string, an exclusive-OR operation with a predetermined byte-constant.
6. A method as in claim 5 wherein the predetermined byte-constant comprises a hexadecimal value "5A".
7. A method as in claim 1 wherein the disk drive of the computer system comprises an IDE disk drive.
8. A method as in claim 7 wherein the disk drive of the computer system includes an integrated controller conforming to the ATA interface standard.
9. A method as in claim 1 wherein the method steps recited therein are performed by the computer system under control of software resident within a non-volatile memory.
10. A method as in claim 1 wherein the recognition table is updateable.
11. A method as in claim 1 wherein the recognition table and the configuration table are combined into one table.
12. In a computer system having a disk drive and having a configuration memory, a method of conditionally specifying to the computer system a plurality of drive parameters appropriate for the disk drive, absent any interaction with a user of the computer system, comprising the steps of: sending a model-identification-query to the disk drive, said model-identification-query causing the disk drive to return a model-identification-string which identifies the disk drive's manufacturer and model number; encrypting the model-identification-string returned from the disk drive, thereby forming an encrypted returned model-identification-string; comparing the encrypted returned model-identification-string against a plurality of entries within a recognition table, said recognition table containing an entry for each of a plurality of disk drives, by vendor and model number thereof, which are each known to perform satisfactorily with the computer system, said recognition table being pre-stored within the computer system and containing, for each entry, a field specifying a pre-encrypted permissible model-identification-string for the respective entry and a field specifying a corresponding drive-type-number for the respective entry, said pre-encrypted permissible model-identification-strings being pre-encrypted in like manner as in the encrypting step, said comparing step for finding an entry within the recognition table corresponding to the returned model-identification-string, if such a matching entry is present within the recognition table, and otherwise for determining that no matching entry is present within the recognition table; retrieving, upon finding a matching entry within the recognition table, the drive-type-number corresponding thereto; and storing, upon retrieving a drive-type-number from the recognition table, the retrieved drive-type-number into the configuration memory of the computer system; whereby the drive parameters appropriate for the disk drive are specified to the computer system by reference to a pre-stored configuration table using the retrieved drive-type-number previously stored within the configuration memory, said configuration table containing, for each drive-type-number from a group of known drive-type-numbers, a corresponding plurality of drive parameters.
13. A method as in claim 12 wherein the encrypting step comprises the step of performing, for each byte of the returned model-identification-string, an exclusive-OR operation with a predetermined byte-constant.
14. A method as in claim 13 wherein the predetermined byte-constant comprises a hexadecimal value "5A".
15. A method as in claim 12 wherein the disk drive of the computer system comprises an IDE disk drive.
16. A method as in claim 15 wherein the disk drive of the computer system includes an integrated controller conforming to the ATA interface standard.
17. A method as in claim 12 wherein the method steps recited therein are performed by the computer system under control of software resident within a non-volatile memory.
18. A method as in claim 12: wherein the modal-identification-string returned from the disk drive includes a plurality of drive parameters appropriate for the disk drive; and wherein each of the plurality of permissible model-identification-strings stored within the recognition table includes a plurality of drive parameters appropriate for a disk drive corresponding to the respective entry; and wherein the comparing step finds a matching entry within the recognition table only if the plurality of drive parameters contained within the returned model-identification-string matches an entry within the recognition table.
19. A method as in claim 12 wherein the reception table is unpdateable.
20. A method as in claim 12 wherein the recognition table and the configuration table are combined into one table.
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