WO2004105018A1

WO2004105018A1 - Time slip mode setting

Info

Publication number: WO2004105018A1
Application number: PCT/IB2004/050570
Authority: WO
Inventors: Robert A. Brondijk; Stephanus J. M. Van Beckhoven
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2003-05-20
Filing date: 2004-05-04
Publication date: 2004-12-02
Also published as: TW200506834A

Abstract

An recording device has medium interface means (14) for interfacing with a storage medium (11) for recording data on the medium and retrieving data from the medium, and a host interface (15) for communicating with a host (13) via messages according to a protocol (ATA/ATAPI). The messages include a write command for writing data in real-time, and a read command for reading data in real-time. The device has a mode unit (16) for setting the device in a special mode for simultaneously recording and playback of data in real time. In the special mode rotation speed differences of the storage medium (11) during reading and writing are reduced for allowing fast interleaving of reading and writing. A mode indicator is transferred via the host interface (15) for engaging the special mode.

Description

Time slip mode setting

The invention relates to a device for storing information on a storage medium, the device comprising medium interface means for interfacing with the storage medium for recording data on the medium and reading data from the storage medium, and host interface means for communicating with a host via messages according to a protocol, the messages including a write command for writing data in real-time and a read command for reading data in real-time.

The invention further relates to a method of controlling a rotation speed in a device for storing information on a storage medium, the method comprising communicating with a host via messages according to a protocol, the messages including a write command for writing data in real-time and a read command for reading data in real-time.

The invention further relates to a method of controlling the device, the method comprising communicating with the device via messages according to a protocol, the messages including a write command for writing data in real-time and a read command for reading data in real-time.

The invention further relates to a computer program product for storing information on a storage medium, and for controlling the recording device.

Controlling of storing information on a storage medium such as an optical record carrier via a recording device is known from the DVD (Digital Versatile Disk) system and a draft proposal of the National Committee for Information Technology Standards (NCITS): Working Draft, T10/1363-D, Revision lOg, November 12, 2001, "INFORMATION TECHNOLOGY - SCSI Multimedia Commands - (revision MMClOg, in this document further called MMC-3). The device has a medium interface, e.g. a read/write head and positioning system, on one side to interface with the storage medium. On the other side, the recording device has a host interface to communicate with a host, which may be a PC or the application unit of a video recorder. A protocol for communicating between the host and the host interface of the recording device is the ATA/ATAPI standard referred to in MMC-3 (chapter 1) and in particular NCITS T13/1321D AT Attachment with Packet Interface 5 referenced in MMC-3 (chapter 2.1.2), or X3T13/1153D ATA-5 Rev. 17, further called ATA/ATAPI-5. Hence the device may be called an ATA/ATAPI device. Such recording devices are being used for recording real-time data blocks, e.g. video, under the control of the host system. The host accommodates applications like recording or playback of video. Simultaneously recording and playback of real-time data like video is used for rendering a first recorded part of a video program while still recording a second part. Such a combination is commonly called time slip mode. Also a real time program may be recorded while rendering a different program recorded earlier, or a different combination of programs may be recorded / retrieved. The existing recording devices cannot easily perform the required simultaneous playback and/or recording operations, and also optimally perform other data storage operations.

Therefore it is an object of the invention to provide a storage system that allows simultaneous real-time recording and playback, and other data storage operations.

According to a first aspect of the invention the object is achieved with a device for storing information as described in the opening paragraph, the device comprising mode means for setting the device in a special mode for simultaneously recording and playback of data in real time, in which mode a rotation speed of the storage medium during reading is controlled to a reading rotation speed near a rotation speed during writing, the reading rotation speed being lower than a maximum possible rotation speed for reading, and for engaging the special mode in dependence of a mode indicator received via a mode message by the host interface means.

According to a second aspect of the invention the object is achieved with a method of controlling a rotation speed as described in the opening paragraph, the method comprising setting the device in a special mode for simultaneously recording and playback of data in real time, in which mode a rotation speed of the storage medium during reading is controlled to a reading rotation speed near a rotation speed during writing, the reading rotation speed being lower than a maximum possible rotation speed for reading, and engaging the special mode in dependence of a mode indicator received via a mode message.

According to a third aspect of the invention the object is achieved with a method of controlling the recording device as described in the opening paragraph, the method comprising setting a special mode in the device by sending a mode message including a mode indicator, the special mode being arranged for simultaneously recording and playback of data in real time, in which mode a rotation speed of the storage medium during reading is controlled to a reading rotation speed near a rotation speed during writing, the reading rotation speed being lower than a maximum possible rotation speed for reading.

The effect of the measures is that the device is set to the special mode for interleaving read and write operations under control of the application in the host via the message having the mode indicator. In particular this affects the rotation speed, which is controlled to reduce the changes in speed between reading and writing. Such rotation speed changes occur when reading a disc shape storage medium carrying data at constant linear density (e.g. a CD or DVD). For a maximum data rate during reading the rotation speed of such a record carrier is controlled during normal read operations to a maximum rotation speed that can be handled by the read system, e.g. by the detecting circuits and decoder circuits. Hence at an inner radial position the rotation speed will be higher than at an outer radial position. By setting the special mode the rotation speed differences between read and write are reduced. This has the advantage that, when switching between reading and recording, additional delay time for adjusting the rotation speed is reduced. Further also power consumption, heat production, and mechanical noise are reduced.

In an embodiment of the device the mode means comprise a speed table for controlling, in the special mode, the rotation speed of the storage medium to the reading rotation speed in dependence of a switch between writing and reading. This has the advantage that the rotation speed during the special mode is controlled in a predefined way according to the speed table.

In an embodiment of the device the host interface means are arranged for receiving as the mode message a command including the mode indicator in a mode page. In an embodiment of the method of controlling the device said communicating includes sending as the mode message a command including the mode indicator in a mode page. The effect is that a mode-page to enable the feature of interleaved recording and/or playback is specified. The mode indicator is transferred via the mode page, which mode page is part of a command. This has the advantage that the mode page clearly defines the required operational mode of the device. Further preferred embodiments of the method and device according to the invention are given in the further claims. These and other aspects of the invention will be apparent from and elucidated further with reference to the embodiments described by way of example in the following description and with reference to the accompanying drawings, in which

Figure 1 shows a disc-shaped storage medium, recording device and host system,

Figure 2 shows a mode page for Fast Mode for Interleaved Write Read On/Off,

Figure 3 shows valid values for a mode page of Fast Mode for Interleaved Write Read On/Off, Figure 4a shows connectors on a drive for interfacing, and

Figure 4b shows an IDE connector layout.

In the Figures, elements which correspond to elements already described have the same reference numerals.

Figure 1 shows a disc-shaped storage medium, recording device and host system. A storage medium 11, for example an optical disc, constitutes a record carrier for a recording device 12. A DVD+RW is an example of such a record carrier. A number of interfacing functions of the recording device is defined according to a predefined standard, for example ATA/ATAPI-5. Hence the device may be called an ATA/ATAPI device. The device (12) has a medium interface, e.g. a read/write head, positioning servo system and control circuits commonly known from the CD or DVD system, on one side to interface with the storage medium 11, for example the DVD+RW disc. On the other side, the device 12 has a host interface 15, e.g. an ATA cable, to communicate with a host, which may be either a PC or the application side of a video recorder, e.g. having usual elements for input and output of video information. The combination of the four elements: DVD+RW medium, a ATA/ATAPI device plus Host, can form a Consumer DVD+RW Video Recorder. The device has a mode unit 16 for setting the device to a special mode for fast switching between reading and writing as described in detail below. The main focus of this invention is of the application in a DVD+RW Video Recorder.

Background information on the recording devices and storage medium formats can be found in the following references: [DVD] Specification for Read-only disc ECMA-267

[DVD+R] 4.7 Gbytes Basic Format Specifications System Description 1.1 [DVD+RW] 4.7 Gbytes Basic Format Specifications Rewritable version 1.2

Commonly in recording systems the following definitions are used. Drive: The unit that interfaces to the storage medium, e.g. has an Optical Pick-up

Unit, servo, data-path, memory flash, and which is interfaced to a host, e.g. with ATAPI. Disc: Can be any optical disc, e.g. CDDA, CD-R/RW, CD-ROM, DVDROM

,DVD+RW, DVD+R SACD

ECC: This is the smallest data amount that can be written on the disc. On DVD a complete EFM block of 32Kbytes user-data. Sector: Is the minimum data size that can be addressed (on DVD) 2048Byt.es Application: Active unit in a host to interface with, which requires real-time data to be stored on the disc (and retrieved from) the disc, and arranges the structure on the disc, and that is for example encoding/decoding the video signals. Chunk a block of data to be written continuously without linking.

De-iced: The +RW phase change material has two states: amorphous or crystalline. All of the material on a new disc has the same state; such a disc is referred to as "iced". By writing to the disc, transitions are created. This influences the reflectivity of the disc and how the disc can be read. If the disc contains iced areas, the current position of the laser can only be determined by via the wobble. In written areas, the position information is included in the data. Off-Track When the laser in the optical pickup unit can not follow the (wobbled) groove on a (recordable) disc it will be off track.

In the following the medium and the protocol over the host interface 15 or ATA cable will more deeply be described. There is a problem in the definition of the protocol as given in MMC-3 and by understanding the relationship between the medium and the protocol, the solution to this problem can be understood.

The ATA cable and its protocol, that are well-known, are described in numerous documents, e.g. the ATA/ATAPI-5 document. The highest protocol level of the cable is given in MMC-3. In the following explanation the storage medium 11 is a DVD+RW medium, a recordable Digital Versatile Disc. The medium is described in the DVD+RW Physical Format Specification.

The problems, which are addressed here, are related to time slip, which is a special mode of the drive which allows it to simultaneously record and playback data in a special mode. The application which is being executed in the host, is recording a real-time program and requires writing of data to the disc in real-time, and at the same time playbacks a real-time program and requires reading of data from the disc in real-time. In an embodiment this mode is executed using a special "speed table', a table specifying the rotation speed given a switch between read and write.

Time slip and rotation speed control for simultaneous recording and playback are described in the non-prepublished patent application of the same applicant, European Patent Application No. 02077985.6, filed on July 22, 2002. However, such a speed control can not be implemented as the standard mode of the drive because of performance loss. Performance is lost, because in the special mode, the read speed is kept in the area of the write speed. On the contrary, for PC data processing programs and consumer requirements, the read speed must go to maximum speed which is possible during reading. Hence the inventors have seen that there is a need for different modes, and that the drive must switch between the modes. Hence, a mechanism is needed to realize the switch between the modes. For this mechanism a mode indictor is sent from the host to the device for setting the mode, for example at least a real-time interleave mode (for time slip and similar purposes) and a data mode (for use with an application which requires maximum data read speeds).

In an embodiment, similar to existing commands of IDE (ATA/ATAPI-5), a mode-page is defined for transferring a mode indicator for setting the special mode. An example is the definition of such a mode page as described with Figure 2.

Figure 2 shows a mode page for Fast Mode for Interleaved Write Read On/Off. The mode page is specified by a table defining the function of a number of bytes constituting a message to be transferred via the host interface. In a first byte 21 a page code is defined, which indicates that the message is a mode page. In further bytes 22 a Page Length is defined, and in a fifth byte a special mode indicator 23 is included to set a fast interleave mode in the device. The mode page constitutes a Fast Mode for Interleaved Write Read On/Off Page, using Page Code 3 lh. The page as shown in figure 2 provides a host the option to preset a special mode for fast switching from read to write and again to recording, to enable playback during recording. The effect is for the read speed there will be a small speed adjustment. This feature is switched on by the Fast interleave indicator.

Figure 3 shows valid values for a mode page of Fast Mode for Interleaved Write Read On/Off. The allowed values for the parameters in the mode page as shown in Figure 2 are specified by a table defining the values for number of the fields constituting the mode page. For the fast interleave indicator 31 a bit is available, when set to one (lb) (as indicated in the valid values column 32) specifies that fast interleave is activated. When set otherwise, the read speed will be changed to the normal DVD read speed, i.e. the maximum possible read speed. A default value is indicated in Default column 33; for the fast interleave indicator the Default = off.

Hence the host interface communicates with the host via messages according to a protocol (e.g. ATA/ATAPI-5), the messages including a write command for writing a series of data blocks in real-time, and a read command for reading a series of data blocks in real-time. For setting the special fast interleave mode a mode indicator is included, e.g. in a mode page as indicated above.

Figure 4a shows connectors on a drive for interfacing. A rear side 71 of a drive is shown. The connector in the rear side of the drive is a 5-in-l connector. A first connector 72 is a digital output, and a second connector 72 is an analogue audio output (4 pin, according to MPC-2 spec). The audio outputs may be not supported. A Master / Slave connector 73 is a 3 position jumper block, for CS (Cable Select), M (Master) and S (Slave), and a jumper 75 is shown in a position as default jumper master select. A fourth connector 76 is a 16 pin ATA-2 dual row flat-cable connector, shrouded & keyed (pin 20 removed). This connector, also called IDE connector, is used for interfacing to a host via an ATA cable as described in ATA/ATAPI-5. Finally a connector 77 is a DC Power inlet according to Industry std. 4-pin Amphenol. The DC Power Connector provides the drive with DC power (+5 Volt and +12 Volt) to be supplied from an external power supply.

Figure 4b shows an IDE connector layout defining the function of the pins. For a detailed description see ATA/ATAPI-5. The data connector is used for interfacing to a host system. The Master / Slave Connector 73 is used to install an IDE data cable depending on the existing PC configuration. There are three possibilities of connection: device as slave (jumper on Slave); device as master (jumper on Master Default); device as master or slave (jumper on Cable Select): depending on the configuration of another connected device. No Jumper also means Cable select.

Although the invention has been mainly explained by embodiments using DVD+RW optical discs, the invention is also suitable for other record carriers such as rectangular optical cards, magneto-optical discs, high-density (Blu-ray) discs or any other type of information storage system for recording series of data blocks in real time. Further simultaneous recording of a first data stream and playback of a second data stream has been used in the examples, but also recording two streams or playback of two streams, or any combination of a number of real time streams can be performed using the special interleave mode. It is noted, that in this document the word 'comprising' does not exclude the presence of other elements or steps than those listed and the word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements, that any reference signs do not limit the scope of the claims, that the invention may be implemented by means of both hardware and software, and that several 'means' or 'units' may be represented by the same item of hardware or software. Further, the scope of the invention is not limited to the embodiments, and the invention lies in each and every novel feature or combination of features described above.

Claims

CLAIMS:

1. Device for storing information on a storage medium (11), the device comprising

- medium interface means (14) for interfacing with the storage medium (11) for recording data on the medium and reading data from the storage medium, - host interface means (15) for communicating with a host (13) via messages according to a protocol, the messages including a write command for writing data in real-time and a read command for reading data in real-time, and

- mode means (16) for setting the device in a special mode for simultaneously recording and playback of data in real time, in which mode a rotation speed of the storage medium during reading is controlled to a reading rotation speed near a rotation speed during writing, the reading rotation speed being lower than a maximum possible rotation speed for reading, and for engaging the special mode in dependence of a mode indicator received via a mode message by the host interface means.

2. Device as claimed in claim 1 , wherein the mode means ( 16) comprise a speed table for controlling, in the special mode, the rotation speed of the storage medium to the reading rotation speed in dependence of a switch between writing and reading.

3. Device as claimed in claim 1 , wherein the host interface means (15) are arranged for receiving as the mode message a command including the mode indicator in a mode page.

4. Method of controlling a rotation speed in a device for storing information on a storage medium, the method comprising

- communicating with a host via messages according to a protocol, the messages including a write command for writing data in real-time and a read command for reading data in real-time, and - setting the device in a special mode for simultaneously recording and playback of data in real time, in which mode a rotation speed of the storage medium during reading is controlled to a reading rotation speed near a rotation speed during writing, the reading rotation speed being lower than a maximum possible rotation speed for reading, and

- engaging the special mode in dependence of a mode indicator received via a mode message.

5. Method as claimed in claim 4, wherein said communicating includes receiving as the mode message a command including the mode indicator in a mode page.

6. Method of controlling a device for storing information on a storage medium as claimed in claim 1, the method comprising

- communicating with the device via messages according to a protocol, the messages ' including a write command for writing data in real-time and a read command for reading data in real-time, and setting a special mode in the device by sending a mode message including a mode indicator, the special mode being arranged for simultaneously recording and playback of data in real time, in which mode a rotation speed of the storage medium during reading is controlled to a reading rotation speed near a rotation speed during writing, the reading rotation speed being lower than a maximum possible rotation speed for reading.

7. Method as claimed in claim 6, wherein said communicating includes sending as the mode message a command including the mode indicator in a mode page.

8. Computer program product for storing information on a storage medium, which program is operative to cause a processor to perform the method as claimed in any of the claims 4 to 7.