Abstract:
The present invention is directed towards reducing hard disk drive (HDD) activity by sharing the buffering activity between a provisional load sharing buffer (PLSB) and a time shift buffer (TSB). The HDD may be included in a digital host communications terminal (DHCT). Initially, the PLSB buffers initial streaming programs to accommodate for channel changes. Additionally, the streaming program is buffered in a standard definition quality regardless of the format of a connected television. Once a predetermined time has passed determined by the size of the PLSB without a channel change, the TSB begins buffering the streaming program. The TSB can then switch between buffering a high definition quality to a standard definition quality of a streaming high definition program depending on other factors to further decrease the HDD activity. Additionally, the TSB can be disabled to prevent buffering of the streaming program.

Description:
RELATED APPLICATIONS 
       [0001]    The present invention is related to attorney docket no. A-11021 entitled “Systems and Methods to Improve Consumer Product Reliability and Lifetime of a Hard Disk Drive by Reducing its Activity,” having common inventors and concurrently filed herewith. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention is generally related to a digital home communications terminal (DHCT) in a communications system and, more particularly, is related to systems and methods for improving product reliability and lifetime of an included hard disk drive (HDD) by load sharing with a provisional buffer. 
       BACKGROUND OF THE INVENTION 
       [0003]    Hard disk drives (HDDs), more than most other electronic components, experience degradation in performance and eventual failure when subjected to temperature extremes that are often found inside digital home communications terminals (DHCTs) or other consumer products. The chance of failure is higher in proportion to the amount of hard drive activity at higher temperatures. Accordingly, once the HDD&#39;s platter and read/write heads begin to degrade, the resulting data errors cause the drive to work harder in an attempt to recover the errors, and this excessive activity increases the chance of even more degradation. There is a need, therefore, for systems and methods that decrease the HDD activity at appropriate times in order to increase the lifetime of the HDD. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0005]      FIG. 1  illustrates a block diagram of a typical DHCT that receives forward signals and transmits reverse signals from a communications network. 
           [0006]      FIG. 2  illustrates an example of the HDD that is suitable for use in the DHCT of  FIG. 1 . 
           [0007]      FIG. 3  illustrates a first embodiment of a block diagram of a DHCT that is suitable for use in implementing the present invention. 
           [0008]      FIG. 4  illustrates a second embodiment of a block diagram of a DHCT that is suitable for using in implementing the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    The preferred embodiments of the invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Furthermore, all “examples” given herein are intended to be non-limiting. 
         [0010]    The present invention is directed towards the enablement of reducing HDD activity, thereby improving the reliability and increasing the lifetime of the HDD. In a DHCT, an HDD may be used to store programs for viewing later. Disadvantageously, in the event of an HDD failure, the stored programs are typically lost and unrecoverable. Therefore, the reliability and lifetime of the HDD in a DHCT, which may also be known as a digital video recorder (DVR) DHCT, is important to a consumer who has selected to record and save certain programs. 
         [0011]      FIG. 1  illustrates a block diagram of a typical DHCT  110  that receives forward signals and transmits reverse signals from a communications network. The communications network (CN)  105  provides programs and other data to a plurality of DHCTs, where only one DHCT is shown for illustration purposes, over coaxial cable, optical fiber, wireless, or any other means of transmitting signals. The DHCT  110  includes a tuner system  115  that receives the programs and filters one or more selected programs based on commands from a processor and interfaces  120 . The programs streaming on tuned channels may then be provided to a coupled analog backend (ABE)  130  for immediate display, and/or the programs may be stored in an HDD  125  for viewing in the future. Video images of the streaming programs are staged in video memory  135  just prior to being sent to the ABE  130  for display and are typically provided at a rate of 20 to 30 frames per second. The ABE  130  then handles other internal processes, such as receiving video data from the processor  120  and then assembles and sends the data to an appropriate output interface  140 . 
         [0012]    A DHCT  110  typically includes a plurality of different interfaces  140  for outputting the channel to different viewing devices depending upon its format. Some examples of a video interface include a coaxial radio frequency (RF) output that connects to nearly any television and outputs standard definition (SD) video. The television usually tunes the outputted program on channel 3 or 4. RCA phono connectors with composite NTSC or PAL video and audio outputs are also compatible with most of today&#39;s televisions. RCA connectors can carry SD or high definition (HD) analog video in RGB (red, green, blue) format or YPbPr format, which is a variation on RGB. A digitized version of YPbPr could also be carried on the three RCA connectors in a format referred to as YCbCr. The RCA interface is of better quality than the coaxial interface. An S-video interface is a small round mini-DIN connector with a slightly better quality than the RCA interface. High speed interfaces are available in DVI (digital video interface) and HDMI (high definition multimedia interface). 
         [0013]      FIG. 2  illustrates an example of the HDD  125  that is suitable for use in the DHCT  110  of  FIG. 1 . The HDD  125  is used primarily to store programs for playback at a later time. The HDD  125  also comprises a time shift buffer (TSB)  205  for temporarily storing a copy of the program stream on the currently tuned channel regardless of whether or not the HDD  125  is storing the program for later viewing. The TSB  205  may store approximately one hour of programming, thereby allowing a user to use trick play functions, such as pause, rewind, fast forward, stop, etc, while viewing a live program that is being tuned, or streamed. At the end of the TSB buffering limit, the oldest packets of the buffered program are continuously dropped to allow for further buffering of the program streaming on the tuned channel. If it is desired that the program also be saved, the program will be stored on the HDD  125  along with a copy being stored in the TSB  205  for the trick play functions. 
         [0014]    When the tuned channel is changed to another channel, the packets stored in the TSB  205  are subsequently cleared or overwritten to allow for buffering of the new program streaming on the changed channel. If the previous program is being stored on the HDD  125 , a first tuner continues to store the program while a second tuner filters the new program streaming on the changed channel to the TSB  205 . 
         [0015]    Conventionally, the program is buffered in the TSB  205  as received from the tuner system  115 ; for example, an HD quality program is buffered to the TSB  205  in its original HD format or in a compressed format from which the original HD can be reproduced. Accordingly, an HD format program is typically buffered at a higher rate (i.e., more bytes per second are written to the HDD  125 ) and with more data than would be buffered using SD quality. Additionally, the program is always buffered in the TSB  205  even when a user is quickly changing channels. Furthermore, the TSB  205  continues buffering the program streaming on the tuned channel when the DHCT  110  remains on even while the television is turned off. Since the TSB  205  is included in the HDD  125  and is always buffering the program on a tuned channel, the HDD  125  is continuously active. Therefore, the higher the operating temperature of the HDD  125  along with the continuous activity, the more likely the HDD  125  will degrade and may prematurely fail. Accordingly, it is an object of the present invention to minimize the HDD activity. In accordance with the present invention, the HDD activity can be minimized by sharing the buffering load of the tuned channel reducing the activity of the internal TSB  205  and thereby reducing the HDD activity. 
         [0016]    In a preferred embodiment of the present invention, the tuned, or streaming, channel is buffered in a provisional buffer that is not located within the HDD  125 . More specifically, instead of buffering the streaming program in the TSB  205  at all times, a provisional buffer is used to share the load with the TSB  205 . Advantageously, when the provisional buffer is buffering the streaming program, the HDD  125  may at that time be inactive. A provisional buffer may be a separate buffer; however, a preferred embodiment utilizes available video memory  135 , system memory  138 , or HDD cache memory either alone or in combination. 
         [0017]      FIG. 3  illustrates a block diagram of a DHCT  300  that is suitable for use in implementing the present invention. A provisional load sharing buffer (PLSB)  305  is coupled to the processor  120  for receiving the streaming program for a limited duration. In the preferred embodiment, the PLSB  305  is a smaller buffer than the TSB  205  and, as mentioned, may be a combination of the video memory  135 , system memory  138 , HDD cache memory, or a separate device, such as NAND flash. The size of the PLSB  305  along with the rate at which data is being buffered to it can be determined by the system operator or the manufacturer. By way of example, an operator or user can determine whether the PLSB  305  buffers the rate of the streaming program or a reduced rate of the program (e.g., an HD quality compared to an SD quality). Advantageously, the PLSB  305  sharing the load with the TSB  205  allows the HDD  125 , which can be either an internal or an external HDD, to deactivate for a period of time that is proportional to the size of the PLSB  305 . 
         [0018]    The present invention allows the PLSB  305  to buffer the streaming, or currently tuned, program for a shorter duration to accommodate for channel changes without burdening the TSB  205  and hence the HDD  125 . Once the PLSB  305  is full, depending upon its size and the buffering rate, and there has not been a channel change, the processor  120  then transfers the buffered program to the TSB  205 . A first method is to continue buffering the streaming program in the empty PLSB  305  at a determined rate until its contents are full again, at which point, the buffered program is again transferred to the TSB  305 . In this manner, the HDD  125  is inactive for the short duration depending on whether or not the HDD  125  is recording another program on a channel that is not currently being viewed. For example, the PLSB  305  may buffer approximately 5 minutes of a streaming program at a reduced rate before the stored program is either overwritten with a new streaming program on a different channel or is transferred to the TSB  205 . Advantageously, by using the PLSB  305 , the user can still rewind or pause the 5 minutes of programming that is either buffered in the PLSB  305  or that was transferred to the TSB  205  along with decreasing the activity of the HDD  125 . Another method is to buffer the streaming program in the PLSB  305  at a reduced rate until such time as its contents are full. Once the PLSB  305  is full and the channel has not changed, the buffering responsibility may be transferred to the TSB  305  to continue buffering the program. At this point, the TSB  305  may begin buffering the program with the streaming quality (e.g., an HD quality of an HD program) or continue buffering at the reduced rate. 
         [0019]    More specifically, an SD quality of the program may be buffered at all times in the PLSB  305  and also in the TSB  205  when it is appropriate. In this manner, the buffered program does not contain as much data as a buffered HD program, and therefore the HDD  125  does not work as much to store the data. In one embodiment, a reduced video quality is achieved by just buffering the MPEG I-frames and discarding P and B-frames. Another embodiment, may be to re-encode a decimated version of the video sequence (e.g., every other pixel is discarded or adjacent pixels are averaged together) before routing the program to the PLSB  305 , the TSB  205 , or the HDD  125 . It will be appreciated that the viewer of an SD television will not notice the difference during playback of a buffered SD program. Additionally, another option may be to stop buffering the program in the TSB  205 , if necessary, to minimize the HDD  125  activity. If the tuned program(s) was selected for recording onto the HDD  125 , the processor  120  continues to route the program(s) to the HDD  125  for storage. 
         [0020]      FIG. 4  illustrates a block diagram of a DHCT  400  that is suitable for use in implementing the present invention. Buffering an SD quality of the program, buffering the streaming program in the PLSB  305 , or stop buffering the program altogether can be decided based on several factors. In accordance with the present invention, a first factor may be to monitor the temperature of the HDD  125  with an external or internal temperature device  405 . When the temperature rises to a predetermined threshold, a processor  410  may then instruct the TSB  205  to buffer a reduced quality of the program(s) as opposed to an HD quality. Alternatively, the processor  410  may instruct the PLSB  305  to buffer the streaming program until such time as the HDD reduces its internal temperature to an acceptable range. 
         [0021]    Another factor may be to monitor the health of the HDD  125 . The processor  410  may run periodic tests on the HDD  125  to analyze and report HDD performance. If it reports that the HDD  125  is beginning to show signs of malfunction, the TSB  205  can be instructed to begin buffering a reduced quality of the program or completely stop buffering the program and allow the PLSB  305  to buffer the streaming program until further notice. 
         [0022]    Accordingly, systems and methods have been described that increase the lifetime of a HDD  125  by sharing the buffering of a streaming program between the PLSB  305  and the TSB  205 . It should be emphasized that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.