Abstract:
A docking module for conventional small form factor disk drives provides, in one embodiment, space for two such disk drives embedded in tray loaders, within a standard 3.5 inches halve height floppy bay. The docking module provides hot swappable insertion and removal of tray loaders together with disk drives. The bay is provided within a housing member. A button attached to a lever mechanism disconnects the docking module connector from the tray loader connector and partially pull out the loader when the button is pushed; An EMI shield fixedly coupled to the tray loaders each provide a barrier to electromagnetic interference.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to computer equipment, disk drives generally, and particularly relates to docking modules for conventional small form factor disk drives.  
       BACKGROUND OF THE INVENTION  
       [0002]     Computer systems and information networks today require tremendous amounts of data storage. Personal Computer (“PC”) users need to add extra storages, to back up files, to transport large files and to have a portable, personalized environment. Modem mass storage users need to place their personal data and environment on an easy transportable device, thereby enhancing mobility and system flexibility. Rich multimedia content drives the need for larger, faster and smaller disk drives. New means of transporting large files are desired. In the corporate world, users exchange a mobile hard disk drive between a deck top and a mobile system for travel. The same device could be carried to another site and used in a virtual office/shared PC environment.  
         [0003]     Many computer systems, including PC, workstations, servers, and embedded systems are designed to have multiple disk drives included in the system. To increase the reliability, there is a need for failed disk drives to be serviced by removing or hot-swapping the device to an operable computer system, and repairing the broken system online.  
         [0004]     Different approaches are used to achieve these goals. A conventional approach is to use a tape drive, removable disk drives, floppy disks or removable drawers with embedded disk drives. A typical approach for large data file backup is a tape drive providing archival storage. In modem PC applications high capacity ZIP and JAZ drives are used. Over the past ten years optical magnetic media also was used for back up and archival storage.  
         [0005]     High-end systems, such as servers are using RAID technology to store and back up files. RAID systems are designed to provide high capacity data storage with built-in reliability. The systems incorporate a degree of redundancy into the storage mechanism to permit saved data to be reconstructed in the event of single (or more) disk drive failure within disk array. For this purpose a limited quantity of removable dick drives and 5.25″ hot-swap drawers are in use.  
         [0006]     There is no universal approach for different applications. All approaches have numerous difficulties. Tape drives has been perceived to be a less expensive back - up for many years. The main disadvantage of magnetic tapes is that data read/write operations are too slow compared to hard disk drives. Tape drives are so large and slow that they are suitable only for large archives and librarys.  
         [0007]     Floppy disks, because of their relatively limited data storage capability, cannot be used to store large amounts of data. Thus, if a large amount of data is to be transferred from the hard disk drive of a computer, more than a single floppy disk may be required. This increases expenses, tends to be labor-intensive, and requires excessive storage space.  
         [0008]     Hard disk drives are generally known to provide exceptionally rapid data storage and retrieval, as well as high levels of storage capacity. The conventional hard disk drives are permanently mounted in system cabinets. There are several ways to use them as a back up devices. One of the ways is known to provide mirrored drives, in which two functionally identical drives are installed with one drive serving as the back up to the other drive. Permanently installed drives offer little portability. To move the data from one PC to another the power have to be down, the disk drive has to be disconnected and transported to another PC. This operation is time consuming and unhandy. In many systems the mirrored disk drives are mounted in a removable drawers and in the event of failure the disk drive can be disconnected and removed without power down. The embedded conventional drives in the removable drawers are usually 3.5 inch form factor, mounted in 5.25 inch full or halve height drawers. The drives and drawers are too large, heavy, need too much space and also offer limited portability. These disadvantages can be solved by small form factor, high capacity disk drives providing the portability advantages inherent in floppy disks, without sacrificing the data storage capacity of hard disk drives.  
         [0009]     Removable media drives like Iomega ZIP and JAZ drives are known in the industry, and offer some limited success in overcoming a few of the foregoing limitations of conventional prior art systems. For example, SyQuest Technology offers cartridge drives in which the media can be removed from the remainder of the drive. While this approach does offer the ability to expand the capacity of a drive, the media in a SyQuest cartridge is readily exposed to the environment and can easily become contaminated from such exposure, rendering the cartridge useless. In addition, Bernoulli drives offer removable media, but suffer from slow access time and limited reliability. In addition, none of these devices can be readily hot swapped, and each of them has, historically, taken up at least a 5.25 inch half-height drive bay for a single device. Importantly, the limited storage capacity of these devices makes them unsatisfactory as a primary drive or, in at least a number of cases, a backup device.  
         [0010]     Removable disk drives are also well known in the industry. The assignee of the present invention has offered a solution to some of the foregoing limitations of the prior art. The U.S. Pat. No. 5,483,419 entitled “Hot-Swappable Multi-cartridge Docking Module”, describes a docking module for a number of removable hot-swappable disk drives with sufficient capacity to be installed in a computer cabinet as either a primary and secondary drive, or a backup devices. Moreover, the docking module offers relatively fast access times, unlimited expansion of total capacity through the use of multiple drives, and portability. The device disclosed there includes a means for hot swapping of drives, e.g., exchanging drives while the system is still operating without the loss of data, and it also provides two disk drives per 5.25 inch half-height bay. The main disadvantage there is that there are not too many available removable disk drives on the market.  
         [0011]     Development of the disk drive technology and I/O interfaces has created smaller, slimmer and cheaper high capacity disk drives. A lot of companies are manufacturing 2.5 inch high capacity /10 to 80 GB / pocket drives. The I/O Serial ATA interface incorporated in these disk drives make them very suitable, as hot-swappable, removable devices. As a result, there has been a need for smaller 3.5 inch hot-swappable docking modules, which improve upon the foregoing limitations of the prior art.  
       SUMMARY OF THE INVENTION  
       [0012]     The present invention solves the above and other problems, by providing a 3.5 inch halve height docking module with hot-swappable small form factor, high capacity, disk drives embedded in tray loaders.  
         [0013]     The invention in first embodiment, includes 3.5 inch halve height docking module having two thinner drive bays, each capable of receiving a tray loader with embedded 2.5 inch IDE/ATA or Serial ATA disk drives. In addition, an IDE/ATA or Serial ATA bus arrangement is provided so that either or both of the drives can be added or removed from the system without requiring the rest of the system to be shut down.  
         [0014]     Further, a positive insertion and removal structure is provided for ensuring that the drives are fully and correctly inserted and for simplifying the removal of a drive from the module. The insertion and removal structure cooperates with the PCBA back plane to assist in providing the hot swappability mentioned above, by causing power to be disconnected to the drive before the drive is actually disconnected from the backplane connector of the drive module.  
         [0015]     A general object of the present invention is to provide a 3.5 inch halve height-docking module, which provides hot-swappability of small, form factor disk drive within a computer system.  
         [0016]     It is another object of the present invention to provide a docking module having the capacity for multiple thin disk drives within the space of a half-height 3.5 inch bay.  
         [0017]     It is a further object of the present invention to provide a docking module capable of supporting a plurality of disk drives each embedded in tray loader at a density of at least two loaders per 3.5 inch half-height bay.  
         [0018]     It is a still further object of the present invention to provide a means for positive insertion and removal of a disk drive from a bay within a docking module.  
         [0019]     These and other objects, advantages aspects and features of the present invention will be more fully understood and appreciated upon consideration of the following detailed description of preferred embodiments in conjunction with the accompanying drawings. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0020]      FIG. 1  is perspective view of a two-drive docking module in accordance with the first embodiment of the present invention.  
         [0021]      FIG. 2  is perspective view of a two-drive docking module in accordance with the second embodiment of the present invention.  
         [0022]      FIG. 3  is an exploded perspective view of a two-drive docking module of  FIG. 1 .  
         [0023]      FIG. 4  is an exploded perspective view of the tray loader in accordance with the first embodiment.  
         [0024]      FIG. 5  is an exploded perspective view of a two-drive docking module of  FIG. 2 .  
         [0025]      FIG. 6  is an exploded perspective view of the tray loader in accordance with the second embodiment.  
         [0026]      FIG. 7A -B is a schematic block diagram forming the circuitry for providing hot swappability of the drive of  FIG. 1 .  
         [0027]      FIG. 8  shows an alternative embodiment of a docking module for use with ten drives (fife dual docking modules in housing) 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]     Referring initially to  FIG. 1  and  2 , a 3.5 inch half-height docking module  10 , is shown for holding two tray loaders  40  with embedded small form factor disk drives  50 . The docking module is designed to be installed within housing such as a computer chassis or an external housing (not shown). It is to be understood that the docking module  10  fits snugly within a standard-sized 3.5 inch form factor cavity of deck top personal computers.  
         [0029]     As appreciated in reference to  FIGS. 1 and 2 , the portable tray loader  40  with the embedded disk drive can be manually inserted into the docking module  10  and held in operable engagement with the personal computer. When the tray loader  40  with the disk drive is operably engaged with the docking module  10 , data can be stored on the disk drive by the user of the computer system. Then, the tray loader  40  with hard disk drive can be ejected by means of the push button  120  or  130  from the docking module  10  and transported to another location for storage or use.  
         [0030]     In cross-reference to  FIGS. 1 and 3 , the docking module includes a front panel  20  with two slots  30 . The open slot  30  is suitable for receiving a tray loader  40  with embedded disk drive. The tray loader  40  is inserted through the front panel slots into a pair of guides  60  and  70 , which are supported by a base  100 , enclosed at the top by a cover  110 .The base  100  supports at the back thereof, a printed circuit board  80 . The guides  60  and  70  extend from the front panel to the printed circuit board  80 . Two connectors  82 A-B situated on the back plane PCB  80 , are designed to mate with a connector  48  ( FIG. 4 ) on the abutting part of the tray loader to provide power to the drive and communications between the PCB  80 , a conventional host system (not shown) and the drive  50 .  
         [0031]     Each of two push buttons  120  and  130  is connected to an associated slide  90 A or  90 B. The slide  90  in turn moves within a guide channel  62  or  72  in the guides  60  and  70 . The back end of the slide, positioned near to the associated pawl  140  suppress the pawl and extends out the tray loader  40  when the associated button  120  or  130  is pushed.  
         [0032]     As shown in  FIG. 4 , the tray loader in the first embodiment includes EMI shield  42 , Link PCBA  44  with two connectors ( 45 ,  46 ), small form factor IDE disk drive  50  and plastic cover  48 . The EMI shield serves to support the conventional disk drive  50  and Link PCBA  44 . It also prevents electromagnetic influence between the disk drives in the docking module.  
         [0033]     The Link PCBA  44  is mounted on the EMI shield  42  and serves to connect electrically the disk drive  50  with the host. The first connector  45  is 44-pole socket IDE connector, well known in the industry. The second one  46  is a special multi-insertion 50-pole socket PC MIDI connector similar to the so-called PCMCIA connectors. Both connectors are assembled on the link PCB. The plastic cover  48  is covering the PCBA, fixing the disk drive to the EMI shield and serves as a slide of the tray loader.  
         [0034]     As best seen from  FIG. 3 , the printed circuit board  80  in the first embodiment of the docking module may be better appreciated. There are two pin connectors  82 A and  82 B on the front side of the board. The connectors are multi-insertion  50  pin PC MIDI connectors. The connector pins has three different lengths. They enable a power-up delay between the time when power is applied to the drive and the time when the bus is enabled, to allow the drive to spin up and reach a stable state before the bus is enabled. When the drive  50  is inserted manually through the slot  30  and into the guides  60  and  70 , it is gently plugs into the connector  82  on the PCB  80 . By using pins of three different lengths, with the power supply pins being longest, the bus pins being shorter, and the drive output pins the shortest, the power supply connection is made first, with the remaining connections being made at appropriate subsequent times. Momentarily after the short pin connection is made, the host system recognizes the installation of the drive  50 . It will be appreciated that, when the drive is moving into the connector  82  it is pushing the pawl  140 . The pawl  140  is rotated and suppresses the slide  90 , causing movement of the slide  90  and push button outdoors.  
         [0035]     When removing the drive, a user needs to push the button  120  or  130  and cause the slide  90 A or  90 B to move towards the appropriate pawl  140 . The pawl is rotated, suppresses the back end of the drive, and removes the tray loader  40  from the PC MIDI connector  82 .  
         [0036]     An important feature of the present invention is the capability for adding and removing drives while the host system is operating. This feature is called “hot swappability” and is well known in the industry. In the first embodiment  FIG. 1  and  3  of the current invention, this feature implementation is based on keeping the drive in RESET condition while it is inserted or ejected. Thus the drive interface buffers are kept in high Impedance State so no data corruption can occur on the host system bus while the drive&#39;s power supply voltage may become unstable. In order to achieve this goal, a simple electronic circuit is implemented on the back panel PCB and a special design of the 50-pole PC MIDI pin connectors  82 A and  82 B with three different pin lengths is used. All power supply voltage lines and the reset lines are tied to the long pins of the PC MIDI connectors  82 A and  82 B. All interface lines (except RESET) are tied to middle length pins of the PC MIDI connectors  82 A and  82 B and the DEV_ENA signals  160 A and  160 B are tied to the short pin  37  of the corresponding PC MIDI connector  82 A and  82 B.  
         [0037]     Referring to  FIG. 7B  the Link PCB circuit is shown. It can be easily seen that this PCB provides a direct connection for all interface signals between 44-pole IDE connector  45  and 50-pole PC MIDI connector  44 .  
         [0038]     Referring to  FIG. 7A  the back plane PCB electronic circuit is shown. This circuit includes a bus connector  84  for connection to the IDE bus of the host system (not shown) in a conventional manner. In contrast, each of two tray loaders with embedded HDD connects to either PC MIDI connector  82 A and  82 B. For purposes of the discussion, connector  82 A will be defined as the master connector, while connector  82 B will be defined as the slave connector, as required by the CSEL signal  162 A being tied low for the master and CSEL signal  162 B tied high for the slave connector.  
         [0039]     As seen on  FIG. 7A , almost all remaining interface signals are directly tied signals from the bus connector  84  to the corresponding signal pins of both master and slave connectors  82 A and  82 B except the host RESET signal  164 . By implementing three NOR 74HCT02 gates  170 A- 170 C the master and slave RESET signals  166 A and  166 B are asserted when either the host RESET signal  164  is asserted (driven low) or the DEV_ENA signal  160 A-B on pin  37  of the corresponding PC MIDI connector  82 A-B is high level.  
         [0040]     For the purposes of simplicity, insertion and removal of a tray loader into the master slot will be explained; insertion and removal of a tray loader into the slave slot involves identical components and operates in the same way.  
         [0041]     Let us assume now a tray loader  40  with embedded HDD  50  is being inserted into the docking module master slot  30 A. When the tray loader  40  approaches the backplane PCB, all long pins of the master PC MIDI connector  82 A make contact first and thus the HDD is powered and the master slot RESET signal  166 A is tied to the HDD as well. Referring now to  FIG. 7A  it can be noticed the master slot RESET signal  166 A is asserted (low level) at this time as long as the master DEV_ENA signal on pin  2  of the 74HCT02 NOR gate  170 A is tied high through resistor R 4   168 . Thus the HDD  50  is put in reset condition and its interface buffers are in high Impedance State. As the tray loader insertion process continues, the middle length pins of the master slot PC MIDI connector  82 A make contact next and the HDD interface buffers are connected to IDE bus of the host system. At this time the master slot RESET signal  166 A is still asserted and the HDD interface buffers are kept in high Impedance State. A short moment before the tray loader insertion is completed, the short pin  37  of the master slot PC MIDI connector makes contact.  
         [0042]     Referring now to  FIG. 7B , the pins  37  and  38  of the Link PCB PC MIDI socket connector  46  are short-circuited. Thus pins  37  and  38  of the back plane PCB master slot PC MIDI connector  82 A become tied to each other and the master DEV_ENA signal  160 A on pin  2  of the 74HCT02 NOR gate  170 A is connected to the signal ground. When the host system RESET signal  164  is not asserted at this time, the master slot RESET signal  166 A is negated and the HDD embedded into the master slot tray loader is no longer kept in reset condition.  
         [0043]     Once the drive is installed into the system, the system recognizes the drive in the conventional manner, with the exception that the device driver always assigns a drive letter to a slot, whether or not a disk is present. The device driver further provides a software interrupt looking for a drive to be installed in an empty slot. Once a drive is detected by the system, the software interrupt causes the device driver to do a device inquiry command. The drive  50  responds with configuration of heads, cylinders and sectors, which allow the IDE interface with the host to address it. The system then can automatically address the drive and its data without rebooting and during the operation, the drive  50  operates as a conventional HDD.  
         [0044]     When the tray loader  40  is ejected essentially the reverse sequence of the insertion takes place. As soon as the tray loader begins to move out of the docking module, the pin  37  of the master slot PC MIDI connector  82 A is disconnected. Then the signal on pin  2  of a 74HCT02 NOR gate  170 A goes to a high level and hence the master slot RESET signal  166 A is asserted. This puts the drive interface buffers in high Impedance State and prevents the host system bus data of corruption. When the ejection continues, the middle length pins of the master slot PC MIDI connector are disconnected next and the drive interface buffers are physically disconnected from the host system bus while the master slot RESET signal  166 A is still connected to the drive. Since the drive power supply lines and the RESET signal are tied to the long pins of the PC MIDI connector, they are last disconnected during the ejection process.  
         [0045]     In another embodiment of the present invention as shown on FIG. 2  and  5 , another type of tray loader  40  and back plane connectors  83  are in use. The back plane connectors  83  are multi-insertion Serial ATA connectors. The tray loader as shown in  FIG. 6 , includes EMI shield  42 , small form factor Serial ATA disk drive  50  and plastic cover  48 . There is a direct connection between the disk drive and the host. In this case a special multi-insertion Serial ATA plug connector is embedded in the disk drive. The used Serial ATA connector and interface provide the opportunity for disk drives to be hot swappable and inserted directly into receptacles. Serial ATA includes all the mechanical and electrical features necessary to allow disk drives to be inserted into receptacles while the system is powered, and the protocol ensures that disk drive discovery and initialization are handled.  
         [0046]     Referring further to  FIG. 2 , buttons  130  and  120  are engaged in a lever mechanism, which is well-known in the art. When the button  120  or  130  is pressed, one tray loader  40  is disengaged from the connector  83  or the host and ejected from the docking module  10 .  
         [0047]     Referring next to  FIGS. 8A-8B , an alternative embodiment to the design of  FIGS. 1 and 2  may be better understood.  FIG. 8A  is a side elevation view of a docking module  200  capable of holding five docking modules  10 ;  FIG. 8B  is a front view of the same module; each has certain internal components shown for clarity.  
         [0048]     Having fully described a preferred embodiment of the invention and various alternatives, those skilled in the art will recognize, given the teachings herein that numerous alternatives and equivalents exist which do not depart from the invention. Therefore the invention is not limited by the foregoing description, but only by the appended claims.