WO1995008911A1

WO1995008911A1 - Full-height disk drive array support structure

Info

Publication number: WO1995008911A1
Application number: PCT/US1994/010372
Authority: WO
Inventors: Larry Kibler; Bernie Wu; Charles Fishpaugh; Guy Carbonneau
Original assignee: Conner Peripherals, Inc.
Priority date: 1993-09-20
Filing date: 1994-09-14
Publication date: 1995-03-30
Also published as: JPH09505418A

Abstract

A structure for supporting an array of three electrically connected disk drives (22a, 22b) in a full-height drive bay (23) of a personal computer. The drives have a form factor of 3.5', including a height of approximately 1.0'. The array is supported within a substantially cubical cage (20), slightly spaced from each other within the cage so that they are supported on 1.05' centers. The support structure further includes a plurality of disk carriers (44) attached around at least two sides of each of the disk drives to support and properly position the drives within the cage. The disk carriers may be custom fit to any drive design. Thus, subject to the proper size requirement, a wide variety of drives may be utilized within the cage of the present invention.

Description

FULL-HEIGHT DISK DRIVE ARRAY SUPPORT STRUCTURE

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a support structure for a data storage system, and more particularly, to a cage and a plurality of disk drive carriers for supporting an array of disk drives in a full-height disk drive bay of a computer.

Description of Related Art The past few decades have seen a marked increase in the need for data processing systems having higher storage capacities and better performance capabilities. Innovations in magnetic disk drive storage media and recording heads have provided sufficient increases in storage capacities to meet industry demands. Similarly, there have been marked improvements in the performance of the central processing unit (CPU) of the data processor. CPUs today are capable of processing instructions and data several times faster than CPUs of only a few years ago. However, in contrast to the innovations in storage capacity and processing time, the transfer rate of instructions and data between the CPU and the hard drive has undergone only modest improvement. As explained in a 1987 paper entitled, "A Case for Redundant Arrays of Inexpensive Disks (RAID) ", by Patterson et al. from the University of California at Berkeley, unless the input/output (I/O) performance between the CPU and the hard drive is increased, the CPU will process data more quickly only to remain idle during the comparatively slow I/O process.

The Berkeley article suggested that the single hard drive in a data processor should be replaced by an array of interconnected hard drives, each having independent I/O with the CPU. Thus, I/O may occur with several drives in parallel and the transfer rate of instructions and data to and from the CPU may be significantly increased. A problem with using an array of hard drives is that the failure rate of the system as a whole is vastly increased due to the large number of disk drives in the array (each disk drive being a potential source of failure) . Thus, the article suggested that in order to overcome the reliability problem, the array should include extra disks containing redundant information to recover the original information when a disk fails. The article described such an array as a redundant array of inexpensive disks, or "RAID".

An example of an arrayed disk and interface system is disclosed in U.S. Patent No. 5,148,432 to Gordon et al., entitled, "Arrayed Disk Drive System and Method". A disk drive array is disclosed having a large number of channels, each channel comprised of a plurality of disk drives. In a preferred embodiment, the array is comprised of 66 disk drives. Data and instructions to and from the channels are controlled by a plurality of small computer system interface (SCSI) controllers, one SCSI controller per channel. Through the use of a "grey code" generator known in the art, I/O may be conducted through the SCSI controllers with each channel in the array simultaneously.

Up until the present, disk arrays such as those disclosed in Gordon et al. have been used primarily in large computer applications with large numbers of disks. Such systems are equipped for either large volume data transfers at a high transaction rate, or a large number of smaller transactions at a high transaction rate. Furthermore, up until the present, use of a RAID system in a computer has required structural customization of the host computer to provide sufficient space for the disk drive array, as well as electrical customization of the host computer to allow data transfer with the array. Customization of the host computer is expensive and has prevented RAID systems from gaining large scale commercial applicability.

In addition to customization of the host computer, a further disadvantage to conventional RAID systems is that they are dedicated systems; that is, the system is built as a black box which does not allow for alteration or interchangeability of the internal components. While conventional systems provide for replacement of a failed drive, up until now, the replacement drive had to have been customized for use in that RAID system. Presently, conventional RAID systems cannot operate with off-the-shelf disk drives. Off-the-shelf disk drives are standard, non-dedicated disk drives available to end users independent of a particular computer architecture.

A further disadvantage to conventional RAID systems relates to the method of achieving "hot pluggable" disk arrays. An important requirement for RAID systems is that hard drives within the array be provided for removal and replacement without having to power down the array. However, introduction or removal of a disk drive into or from a hot pluggable array presents the problem of contact bounce. When a mechanical contact is made between the power supply and the replacement disk drive, contact lasting only a few hundred milliseconds is made and broken several times before a clean connection is made. By applying and removing power to the disk drives over such short, repeated intervals, electrical noise referred to as contact bounce is generated, which noise has an adverse effect on other signals.

In order to overcome this problem, conventional RAID systems employ a customized sled architecture, which includes a special "make-before-break" edge connector. The special edge connector generally includes power supply and/or ground pins which are longer than the signal pins. Thus, upon introduction of a drive into the array, signals are supplied to the drive only after a clean power connection is made. The special edge connector does not come standard on hard drives, and therefore a custom piece of hardware must be fitted between the standard hard drive connector and the special edge connector. This customization to allow inclusion of the special edge connector further prevents standard, off-the-shelf disk drives from being used in conventional RAID systems.

Coincident with the push toward higher storage capacities and faster processors, there has been a trend toward downsizing computers and the components therein. Portable and lap top computers have created a sizeable market for smaller hard drives and the last ten years has seen a reduction in the industry form factor standard for disk drives from 5 " to 3 " to 2^". The reduction in the size of disk drives has made it possible to include a plurality of disk drives in the drive bay of a personal computer, where previously only one disk drive would fit.

Despite the push toward more compact personal computers, speed and performance continue to be primary design criterion in any commercial system. As in large scale computer applications, the improvement in I/O performance in personal computers has been modest in comparison to advances in processor performance and disk storage capacity. Thus, there is presently a need in personal computers for an improved yet inexpensive system having enhanced I/O performance capabilities.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an ariayed disk drive system fitting within a conventional full-height drive bay of a computer.

It is a further object of the present invention to provide a support structure for the arrayed disk drive system. It is another object of the present invention to provide the arrayed disk drive system and support structure within the drive bay without modification of a conventional drive bay or host computer.

It is a still further object of the present invention to provide a RAID system which may operate with a disk drive array comprised of non-dedicated, off-the-shelf disk drives chosen by the end user.

These and other objects are accomplished by the present invention, which relates to a structure for supporting an array of three electrically connected disk drives in a full-height drive bay of a personal computer. A full-height drive bay is conventionally formed with a width of approximately 5.75", a height of approximately 3.25" and a depth of approximately 8.0". In one embodiment of the invention, the drives have a form factor of 3%", including a height of approximately 1.0". The drives are supported within a substantially cubical cage, slightly spaced from each other within the cage so that they are supported on 1.05" centers. The support structure further includes a plurality of disk carriers attached around at least two sides of each of the drives to support and properly position the drives within the cage. The disk carriers may be custom fit to any drive design. Thus, subject to the proper size requirement, a wide variety of drives may be utilized within the cage of the present invention. When properly positioned within the cage, the drives connect to a SCSI backplane located on the rear wall of the cage. The backplane includes a plurality of SCSI connectors, one for each of the drives in the array, for transferring--power and electrical signals between the disk drives within the array and the CPU in the host computer. The backplane further includes "power on delay" circuitry for delaying power to a disk drive for a predetermined length of time after the drive has been added to the array. The power on delay circuitry allows the drives within the array to be hot pluggable without having to customize the drives to avoid contact bounce.

The cage is mounted in the host computer enclosure by threaded screws provided in the same location and of the same size as in the standard full-height drives. The cage additionally includes several open areas to allow maximum air flow in and around the disk drives to prevent thermal build-up within the drives during operation.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to the drawings, in which:

FIGURE 1 is an exploded perspective view of a disk drive array and cage according to the present invention; FIGURE 2 is a perspective view of a cage according to the present invention;

FIGURE 3 is a sectional view of the cage through line 3-3 in Fig. 2; FIGURE 3a is an enlarged perspective view of the front section of the card guide according to the present invention;

FIGURE 4 is an alternative embodiment of the cage shown in Fig. 3; -— FIGURES 5a and 5b illustrate an embodiment of the present invention including circular open areas on the cage walls;

FIGURE 6a and 6b illustrate an alternative geometry of the present invention including slotted open areas on the cage walls;

FIGURE 7 is a view of the backplane according to the present invention;

FIGURES 8-9 are schematic representations of the electronics included on the backplane shown in Fig. 7; FIGURE 10 is a circuit diagram of the electronics included on the backplane shown in Fig. 7;

FIGURE 11 is a disk carrier according to the present invention;

FIGURE 11a is an enlarged perspective view of the rear section of the disk carrier according to the present invention;

FIGURE 12 is a perspective view of the latch mechanism according to the present invention;

FIGURE 12a is a top view showing the latch mechanism according to the present invention in the locked position;

FIGURE 12b is a cross sectional view of the latch mechanism shown in Fig. 12a in an unlocked position;

FIGURE 13 illustrates the guide rails for mounting the present invention within a full-height drive bay; FIGURE 14 illustrates an alternative embodiment of the present invention including a disk drive status board;

FIGURE 14a is cross sectional view through line 14a-14a in Fig. 14;

FIGURE 15a shows two cages according to the present invention used together in a personal computer; and

FIGURE 15b shows six cages according to the present invention used together in a personal computer.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the Figs. 1 - 15b, the present invention relates in general to a RAID system and support structure for supporting an array of three 3H" form factor disk drives in a full-height drive bay of a "tower" personal computer type enclosure. It is understood, however, that the present invention is intended to operate within any full-height drive bay and includes applications having only two 3%" form factor disk drives or a plurality of smaller form factor disk drives. Moreover, the present invention is not limited to magnetic storage disk drives, and may operate with other types of storage devices such as optical scan recording devices and the like. Referring now to Fig. 1, there is shown a cage 20 for supporting an array 22 of three 3&" form factor disk drives 22_M in a full-height drive bay 23. In a preferred embodiment, the array 22 may be comprised, for example, of three CP-30540 model 3 " form factor disk drives manufactured by Conner Peripherals, 3081 Zanker Road, San Jose, CA 95134. However, as explained hereinafter, an important feature of the present invention is that it may operate with a wide variety of presently available, off-the-shelf data storage devices. The drives 22-._c are supported within the cage slightly spaced from each other on 1.05" centers (i.e.. when mounted within the cage, the distance from the center of one drive to the center of a neighboring drive is 1.05") . Thus, the total height of the disk array is approximately 3.10". The thickness of the top and bottom portions of the cage 20 are approximately 0.048", thus yielding a total height of the cage assembly of just under 3.30". As the height of a conventional full-height drive bay is 3.35", the disk drive array 22 fits snugly within the drive bay. It is understood that the height of the drives and the spacing between the drives in the array 22 may be reduced so that the center to center distance of neighboring drives in the array is less than 1.05".

As shown in Figs. 2 and 3, the cage 20 may be bolted or welded together and preferably formed of 18 GA steel. However, the cage may alternatively be formed of a high strength aluminum or other substantially rigid material having a high resistance to shock and vibration. The cage 20 includes top portion 24, bottom portion 26, sides 28 and 30, and rear portion 32, together yielding overall cage dimensions of approximately 7.0" x 5.75" x 3.30". Top and bottom portions 24 and 26 may preferably be flat.

In a preferred embodiment shown in Fig. 3, the sides 28 and 30 each include three parallel rows of card guides 35 on the interior of the cage 20. The card guides may be formed of a high strength polycarbonate or similar material and secured to sides 28 and 30 through slots formed in sides 28 and 30. The cage may further include tabs 82 in sides 28 and 30 adjacent to the cardguides to prevent the cardguides from being dislodged from sides 28 and 30 in the event of a substantial jolt to the cage. Each of the card guides 35 on one side 28 or 30 is aligned with a corresponding card guide on the opposite side 30 or 28. As will be explained in greater detail below, card guides 35 are provided to receive and support the disk carriers to which the individual disk drives are attached. In this way, the drives are positioned and supported within the cage 20. The card guides 35 further align the drives 22_M to connect to a backplane as explained in greater detail below. Stops 36 are preferably provided on the sides 28 and/or 30 at the rear of the cage to stop the disk carriers 44 and the attached drives when the drives are fully inserted into the cage 20. The stops 36 prevent the carriers 44 from contacting the backplane, which may otherwise cause electrical noise or otherwise damage the backplane 44 over prolonged usage.

In an alternative embodiment shown in Fig. 4, horizontal ledge members 37 may be substituted for card guides 35 as part of sides 28 and 30. Horizontal ledge members 37 may preferably be angled along their length so as to protrude out of the plane of sides 28 and 30 into the interior of the cage 20. The horizontal ledge members 37 provide a ledge on which the disk carriers rest to support and properly position the drives 22_M within the cage 20. Sides 28 and 30 may include angled members 34 at the front and/or rear edges to increase the rigidity and shock resistance of the cage 20. It is further understood that known alternative means of supporting the disk carriers may be substituted for the above disclosure and still be considered within the scope of the invention.

The top portion 24, bottom portion 26 and/or sides 28 and 30 may include cut-out sections to allow maximum air flow in and around the disk drives 22_a_- during operation to prevent thermal build-up within the array. As shown in Figs. 5-6, the configuration of the cut¬ out sections may vary. A preferred embodiment of the present invention includes a plurality of holes as shown in Fig. 5, with each hole having a diameter of 5/8" or less and optimally about 1/4". Disk drives emit a radio frequency during operation which may disadvantageously effect the system. Holes which are larger than this tend to amplify the radio frequency emmitted by the drive. Thus, the configuration of the holes has been chosen to allow a high degree of air flow into cage 20, while maintaining the requisite structural rigidity of the cage and minimizing the radio frequency amplification effect. One or more fans (not shown) may be provided to cool the drive bay area and the power supply. The fans preferably have a noise rating of no greater than 28 db.

The cage 20 may additionally include a front cover 39 (Fig. 4) to provide an aesthetic face plate for the cage which is visible to the operator of the host computer. When a disk drive needs to be replaced, front cover 39 may be opened or removed to allow access to the disk drives 22_M. Front cover 39 may include a lock to allow only authorized individuals to open the front cover 39 to gain access to the disk drive array 22. The lock may be an electronic or mechanical lock.

Rear portion 32 includes a backplane 38 for providing power to the drives 22_a_- and for transferring electrical signals between the drives 22_M and a CPU

(not shown) of the host computer. As shown in Figs. 7- 10, backplane 38 may preferably comprise three small computer system interface, or SCSI, connectors 40_a._c for transfer of the power and electrical signals between the disk drives 22..,. and the backplane 38. Each of the SCSI connectors 40_a._c may preferably be an 80-position Champ edgecard connector. However it is understood that other types of signal connectors, such as conventional pin connectors, may be used as is known in the art. Signals are preferably transferred between the three connectors 40_a._c and a single 50-position header 41, which in turn connects via a ribbon cable to the SCSI bus (not shown) . Power is preferably transferred to the drives 22_a__c through the connectors 40_a^. via a 4-position header 43.

The drives 22_a__c are preferably "hot pluggable", i.e.. the power to the drives is supplied in such a manner as to allow insertion or removal of a drive of the array while the system is powered and working. Thus, failed drives may be replaced with a minimum of lost processing time. In order to avoid the problem of electrical noise generated by made and broken contact upon introduction or removal of a disk drive with or from the backplane, the present invention includes a "power on delay" circuit on the backplane 38. The power on delay circuit supplies power to the drives only when a drive has been inserted into the array for a specified time. This circuit allows disk drives to be hot pluggable without the need for special edge connectors or customization of a disk drive, as in conventional sled disk drive architectures. Therefore, the system of the present invention may be hot pluggable with standard off-the-shelf disk drives.

The power on delay circuit senses for a connection being made between a hard drive and the array back plane connectors 40_a;. When the connection is first sensed, the power on delay circuit is enabled and a time-out is started. The time-out lasts for a period that is longer than any possible contact bounce or power spike that may occur while inserting or removing a drive. Every time a contact is broken, the time-out restarts. Power to the drive is applied through solid state switches only when the time-out period of the delay circuit has run. At this point, power may be supplied to the drive without a danger of contact bounce. The solid state switches are power MOSFETS that can be turned on at very low gate currents and with very little voltage drops. These semiconductors provide a very clean switch of power without switch bounce.

As shown in Fig. 11, in order to guide and align the drives within the cage, each drive is mounted to a disk carrier 44. Disk carrier 44 is preferably formed of .062" thick steel. However, other materials, such as high strength polycarbonates, may also be used. The disk carrier 44 is attached around at least two opposi ;e sides of a disk drive via screws or adhesive and

a flange 46 extending outward from the sides of the drive. When a disk drive of the array is inserted into cage 20, the flanges 46 on both sides of the drive are received within the card guides 35 on opposite sides of the cage 20 to properly align the drive within the cage. In the embodiment including horizontal If dge members 37 (Fig. 4) , upon insertion of a drive into cage 20, the flange 46 rests on top of the horizontal ledge member 37 on opposite sides 28 and 30. If the disk

3 are properly inserted and aligned within cage 20, the header on each drive is press-fit connected to one of the SCSI connectors 40_M, thereby electrically connecting the disk drives within the cage 20. The rear of the disk carrier 44 may include guide pins 45 to guide the disk carrier 44 and the attached drive when the drive is fully inserted into the cage 20. The guide pins 45 prevent carrier misalignment, which may otherwise cause electrical noise or otherwise damage the backplane 44 over prolonged usage. The disk carrier 44 may be custom fit to any type of disk drive design, thus allowing a wide variety of drives to be used within the array.

As seen in Figs. 12a and 12b, the front end of each disk carrier 44 (i.e. the end farthest from the rear portion 32 of the cage) includes a latch mechanism 46 for removably securing a drive within the cage 20. Latch mechanism 46 includes two latch pieces 48a and 48b, one on either side of the front of each disk carrier. Each latch piece 48 includes a hook 50 which engageably hooks into an enlarged recessed section 51 formed in each of the opposing card guides 35. In the locked position shown in Fig. 12a, hooks 50 on latch pieces 48a and 48b are engaged within section 51 to lock the disk drive within the cage 20. As shown in Fig. 12b, when a drive is to be removed, both latch pieces 48a and 48b affixed to that drive are manually swung outward, thereby disengaging hooks 50 from the recessed section 51, and the attached carrier and drive may thereupon be removed. It is understood that any of several known latching mechanisms may be employed to removably secure disk carrier 44 and the attached disk drive within cage 20 and still be within the scope of the invention.

The cage 20 further includes left and right guide rails, 60 and 62, respectively, for positioning and securing the cage 20 within the full-height drive bay of a personal computer. As seen in Figs. 2 and 13, each guide rail includes screw tabs 48 for receiving screws to fasten the cage 20 within the drive bay. The screw tabs 48 are provided on the cage at the same location and are of the same size as in standard full- height drives. Thus, the cage 20 may be fastened within a standard full-height drive bay which is conventionally formed with screw holes which align with the screw tabs 48 on the cage 20. As such, no modification of a conventional drive bay to accommodate the present invention is necessary. Should slight adjustment be required to align the cage within the drive bay, both the left and right guide rails are adjustably secured to the cage by screws 64 fitting through slots 66 on the guide rails 60 and 62. The slots 66 are provided to allow the guide rails to move slightly forward, backward, up or down with respect to the cage. Thus, proper alignment of cage 20 within the drive bay is ensured.

In the alternative embodiment of the present invention shown in Fig. 14, the present invention may include a status board 68 affixed to the side 28 or 30. The status board may include electronics to monitor several functions of the disk drive array, including power supply, front cover lock, fan operation, system temperature and the operation of each of the drives in the array. In a preferred embodiment, the status board 68 is provided to transmit audible or visible signals indicating the status of the various system functions. However, it is further contemplated that the status board 68 may include electronics for receiving signals from a remote location to control system functions. Thus, for example, upon receipt of a given signal from a remote location, the power to the system may be turned on or off, or the access code to disengage the locking device on the front cover may be changed.

With respect to the operation of each of the disk drives, the status board 68 may include light emitting diodes (LEDs) 50_a→. indicating the status of each of the disk drives 22_a._c. The three states indicated by the LEDs are: working, not working, and degraded mode. Thus, for example, when a particular drive is functioning properly, a microprocessor (not shown) responsible for monitoring the status of the drives in a known manner sends a signal to the LED for that drive so that the LED shows green; when that drive has failed, the microprocessor sends a second signal to that LED to turn off the LED; and when the drive is in degraded mode, the microprocessor sends a third signal to the LED so that it shows yellow. Degraded mode occurs after a drive in the array has failed. A replacement drive is initially in degraded mode because it has not had a chance to assimilate the data encoded on the other disks. Once the data from the replaced disk drive has been recopied to the new disk drive, the LED for the drive switches to working mode. The status indicators allow an operator monitoring the system to know at any time when a drive needs to be replaced and when the system is not functioning correctly. The LEDs 50,.,. may be located on the status board 68 as shown in Fig. 14. Alternatively, an indicator panel (not shown) may be included on each of the drives, which panel includes the LED indicating the status of that drive. A feature of the present invention is an enhanced flexibility unavailable in conventional RAID systems. As explained in the Background of the Invention section, conventional RAID systems have been designed as black boxes with dedicated components such that they have not allowed for alteration or interchangeability of the types of disk drives used therein. However, by contrast, the present invention has been designed to allow a wide variety of non-dedicated, off-the-shelf drives to be used as part of the array. Thus, hard drives may be used in the array which are available to an end user independent of a particular computer system and which are not manufactured specifically for use within a particular system.

Another feature relating to the flexibility of the present invention is the fact that the system may be provided in any full-height drive bay of a tower-type personal computer. The disk drive array 22 and support structure of the present invention including cage 20, disk drive carriers 44 and backplane 38 provide a system which may be assembled independently of the host computer in which the assembly is to be used. The system comprises a singular unit, which, as with conventional hard drives, may be marketed independently of a particular host computer. Thus, the present invention may be used with a wide variety of available computers and no individualized customization of the host computer is necessary.

More than one cage and disk drive array according to the present invention may be included within a single personal computer. In a preferred embodiment shown in Fig. 15a, two such cages 20 with the disk drive arrays 22 may be provided in side-by-side full- height drive bays 23 within a tower personal computer type enclosure. The two systems may occupy a single channel on the SCSI bus. In an alternative embodiment shown in Fig. 15b, six such cages 20 with the disk drive arrays 22 may be provided in a triple full- height, double wide stand-alone drive bay cabinet 70. The six systems may occupy three channels on the SCSI bus. It is understood that various other numbers of the system of the present invention may be employed within tower personal computer drive bays 23 and/or stand-alone drive bay cabinet 70.

Although the invention has been described in detail herein, it should be understood that the invention is not limited to the embodiments herein disclosed. Various changes, substitutions and modifications may be made thereto by those skilled in the art without departing from the spirit or scope of the invention as described and defined by the appended claims.

Claims

We Claim:

1. A support structure for supporting an array of data storage devices within a full-height drive bay of a host computer, input and output with the data storage devices in the array occurring in parallel, comprising: a cage measuring approximately 7.0 inches by

5.75 inches by 3.30 inches, said cage including means for supporting the data storage devices therein; a plurality of disk drive carriers for attaching to the data storage devices, said plurality of disk drive carriers engaging said support means to position the data storage devices within said cage; and control circuitry within said cage including means for supplying electrical signals to the data storage devices in the array, said support means cooperating with said plurality of disk carriers to align the data storage devices to connect to said electrical signal supply means.

2. A support structure as recited in claim 1, wherein the array of data storage devices comprises three disk drives.

3. A support structure as recited in claim 2, wherein said disk drives have a form factor of 3 inches.

4. A support structure as recited in claim l, wherein said cage is able to accept off-the-shelf data storage devices not dedicated for use within the support structure.

5. A support structure as recited in claim 1, wherein said control circuitry is able to operate with off-the- shelf data storage devices not dedicated for use within the support structure.

6. A support structure as recited in claim 1, wherein walls of said cage include a plurality of open spaces for allowing air flow in and around the array.

7. A support structure as recited in claim 1, wherein a data storage device of the array may be removed and replaced by another data storage device without having to power down the host computer.

8. A support structure as recited in claim 7, further comprising a power on delay circuit for supplying power to a data storage device of the array only after said data storage device has been in contact with said electrical signal supply means for a period of time slightly longer than any possible contact bounce period.

9. A support structure as recited in claim 1, wherein said support means comprises a plurality of parallel horizontal rows of tracks which protrude from at least some side walls of said cage into an interior of said cage, said tracks provided to receive and support said plurality of disk carriers therein.

10. A support structure as recited in claim 1, wherein said support means comprises a plurality of parallel horizontal rows of ledge members which protrude from at least some side walls of said cage into an interior of said cage, said plurality of parallel horizontal rows of ledge members providing ledges on which said plurality of disk carriers are supported.

11. A support structure as recited in claim 1, wherein a center with respect to a height of a first data storage device of the array is approximately 1.05 inches away from a center with respect to a height of a second data storage device of the array, said second data storage device neighboring said first data storage device.

12. A support structure as recited in claim 1, wherein said means for providing electrical signals to the data storage devices in the array comprises a plurality of small computer system interface (SCSI) connectors, one SCSI connector for each data storage device in the array.

13. A support structure as recited in claim 1, wherein said cage is bolted together from steel.

14. A support structure as recited in claim 1, wherein said cage is welded together from steel.

15. A support structure as recited in claim 1, wherein said plurality of disk carriers are formed from steel.

16. A support structure as recited in claim 1, wherein said plurality of disk carriers may be custom fit to any data storage device.

17. A support structure as recited in claim l, wherein said plurality of disk carriers are affixed to the data storage devices by screw means.

18. A support structure as recited in claim 1, further comprising latch means for removably securing a data storage device of the array within said cage.

19. A support structure as recited in claim 1, further comprising status indication means for indicating the status of each data storage device in the array.

20. A support structure as recited in claim 19, wherein said status indication means indicates whether a data storage device of the array is working or is not working or has been recently added to the array and has not yet assimilated data from other data storage devices in the array.

21. A support structure as recited in claim 19, wherein said status indication means comprises at least one light emitting diode for each data storage device in the array.

22. A support structure for supporting a redundant array of disk drives within a full-height drive bay of a host computer, input and output with the disk drives in the array occurring in parallel, comprising: a cage measuring approximately 7.0 inches by

5.75 inches by 3.30 inches, said cage including means for supporting three disk drives spaced from each other within said cage so as to be on 1.05 inch centers; a plurality of disk drive carriers for attaching to the disk drives in the array, said plurality of disk drive carriers engaging said support means to position the disk drives within said cage; and a backplane within said cage including electrical connectors for supplying electrical signals to each disk drive in the array, said support means cooperating with said plurality of disk carriers to align the disk drives to connect to said electrical connectors upon insertion of the disk drives into said cage.

23. A support structure as recited in claim 22, wherein a disk drive of the array may be removed and replaced by another disk drive without having to power down the host computer.

24. A support structure as recited in claim 22, wherein said support means comprises a plurality of parallel horizontal rows of tracks which protrude from at least some side walls of said cage into an interior of said cage, said tracks provided to receive and support said plurality of disk carriers therein.

25. A support structure as recited in claim 22, wherein said disk drives are not dedicated for use within the support structure.

26. A support structure as recited in claim 22, wherein said electrical connectors comprise a plurality of small computer system interface (SCSI) connectors, one SCSI connector for each drive in the array.

27. A support structure as recited in claim 22, further comprising status indication means for indicating the status of each disk drive in the array.

28. A support structure as recited in claim 27, wherein said status indication means indicates whether a disk drive of the array is working or is not working or has been recently added to the array and has not yet assimilated data from other disk drives in the array.

29. A support structure as recited in claim 27, wherein said status indication means comprises at least one light emitting diode for each disk drive in the array.

30. A data storage system for a personal computer, comprising: an array of data storage devices, each data storage device provided for storing data from the computer, data transfer occurring with each data storage device in the array in parallel; a cage measuring approximately 7.0 inches by 5.75 inches by 3.30 inches in which said array is housed; means for supporting said data storage devices within said cage so as to be on 1.05 inch centers; a plurality of disk drive carriers attached to said data storage devices for engaging said support means to position said data storage devices within said cage; and a backplane within said cage including electrical connectors for supplying electrical signals to each disk drive in the array, said support means cooperating with said plurality of disk carriers to align the disk drives to connect to said electrical connectors; wherein said array and said cage form a single unit which is provided within a full-height drive bay of the computer without requiring customization of the computer to operate with the data storage system.

31. A data storage system for a personal computer as recited in claim 30, wherein said array of data storage devices comprises three disk drives.

32. A cage for housing a redundant array of disk drives within a personal computer, comprising: a top section; a bottom section opposed to said top section; at least two side walls adjoining with and orthogonal to said top section and said bottom section; a rear section adjoining with and orthogonal to said top section, said bottom section and said at least two side walls; a plurality of tracks secured to opposite side walls of said at least two side walls, at least a pair of tracks being provided for each disk drive in the redundant array of disk drives, said pair of tracks supporting a disk drive of the redundant array of disk drives within the cage; and wherein the cage is sized to fit within a conventional full-height drive bay of the personal computer.

33. A cage for housing a redundant array of disk drives within a personal computer as recited in claim 32, further comprising a control circuitry mounted to the cage and connecting with the redundant array of disk drives for electrically connecting the redundant array of disk drives with the personal computer.

34. A cage for housing a redundant array of disk drives within a personal computer as recited in claim 32, further comprising a front cover for enclosing the redundant array of disk drives within the cage and which front cover may be opened to allow access to the redundant array of disk drives.

35. A cage for housing a redundant array of disk drives within a personal computer as recited in claim 34, wherein said front cover includes locking means to prevent unauthorized access to the redundant array of disk drives.

36. A cage for housing a hot pluggable array of disk drives within a personal computer, comprising: a plurality of adjoining walls; and means mounted on at least one of said plurality of adjoining walls for supplying electrical signals to a disk drive of the array of disk drives, said electrical signal supply means including means for supplying power to said disk drive only after said disk drive has been in contact with said electrical signal supply means for a period of time slightly longer than any possible contact bounce period.

37. A cage for housing a hot pluggable array of disk drives within a personal computer as recited in claim

36, wherein the cage has overall dimensions of approximately 7.0" x 5.75" x 3.30".

38. A cage for housing a hot pluggable array of disk drives within a personal computer as recited in claim 36, wherein said means for supplying power to said disk drive only after said disk drive has been in contact with said electrical signal supply means for a period of time slightly longer than any possible contact bounce period comprises a timer delay circuit.

39. A data storage system for providing a redundant array of disks drives in a personal computer, comprising: a cage sized to fit within a full-height drive bay of the personal computer; support means mounted on walls on an interior of said cage for supporting disk drives of the redundant array of disk drives within said cage; control circuitry mounted to said cage, said support means supporting said disk drives within said cage for connection with said control circuitry, said control circuitry electrically connecting the redundant array of disk drives with the personal computer; and wherein the data storage system is able to operate with off-the-shelf disk drives in the redundant array which are not dedicated for use within the system.

40. A data storage system for providing a redundant array of disks drives in a personal computer as recited in claim 39, wherein the redundant array of disk drives are hot pluggable.

41. A data storage system for providing a redundant array of disks drives in a personal computer as recited in claim 40, further comprising means for supplying power to a disk drive of the array only after said disk drive has been in contact with said control circuitry for a period of time slightly longer than any possible contact bounce period.

42. A data sto age system for providing a redundant array of disks drives in a personal computer, comprising: a cage; support means mounted on walls on an interior of said cage for supporting disk drives of the redundant array of disk drives within said cage; control circuitry mounted to said cage, said support means supporting said disk drives within said cage for connection with said control circuitry, said control circuitry electrically connecting the redundant array of disk drives with the personal computer; wherein the data storage system is able to operate with off-the-shelf disk drives in the redundant array which are not dedicated for use within the system; and wherein the redundant array of disk drives and said cage form a single unit sized to fit within a full-height drive bay of the computer without requiring customization of the personal computer to operate with the data storage system.

43. A personal computer, comprising: a tower personal computer type enclosure; a central processing unit within said enclosure for processing data and instructions; a cage mounted within a conventional full-height drive bay of said enclosure; an array of data storage devices removably provided within said cage, input and output of data occurring between said central processing unit and each data storage device of said array of data storage devices in parallel, said cage including means for transferring signals and power from the computer to said array of data storage devices; and means for allowing replacement of a data storage device of said array of data storage devices without having to power down the computer.

44. A personal computer as recited in claim 43, wherein said cage may be mounted within said conventional full-height drive bay without alteration of said conventional full-height drive bay.

45. A personal computer as recited in claim 43, wherein said array of data storage devices is able to operate with off-the-shelf data storage devices in said array which are not dedicated for use within said array.

46. A personal computer as recited in claim 43, further comprising a power on delay circuit as part of said signal and power transfer means for supplying power to a data storage device of the array only after said data storage device has been in contact with said signal and power transfer means for a period of time slightly longer than any possible contact bounce period.