EP0126610A2
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Disk drive system
Assignee: EMC Corp
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Filing: 1984-05-15
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Granted: —
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Expires: 2004-05-15
Abstract
Abstract The system comprises a controller connected to a disk drive or drives by a bus including data lines and various control and handshaking lines. One line effects a CONTROL/DATA selection so that the drive knows whether codes sent on the data lines are disk data or drive control instructions. Another line effects a HEADER/DATA selection to distinguish the header and data portions of a disk sector. The controller includes a microprocessor (1911) with a register (1969) holding an expected header EHDR, a register (1967) holding the number SCOUNT of sectors to be read or written and a register (1965) holding the number of codes in a sector. in a read or write operation a signal CTLIDDCA from a sequencer (1945) select HEADER and a receiver, selected by a sequencer signal DP/INT, puts received codes on to a data bus (1913). The microprocessor (1911) receives sector headers in this way until there is a match, whereupon a signal CSIGS is given to the sequencer (1945) which causes CTL/DDCA to select DATA and DP/INT to enable the data receiver or driver depending upon whether the operation is read or write. The codes are counted down by decrementing DCOUNT. When DCOUNT = 0 (end of sector) SCOUNT is decremented and another signal CSIGS causes the sequencer to revert to the conditions for looking for the next expected header which is calculated by the microprocessor and entered in EHDR. Where SCOUNT reaches 0 the read or write operation is complete.
Inventors
- 👤 Edward Gershenson
- 👤 Louis A. Lemone
- 👤 Salvatore Faletra
- 👤 Stephen Caldara
- 👤 Mark C. Lippitt
- 👤 William A. Braun
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 21:13
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/06; G06F3/0601; G06F3/0668; G06F3/0671; G06F3/0673
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
226 words
A disk drive system comprising a controller (107) connected to control apparatus (121) of at least one disk drive (119) by a bus (127) including data transfer lines (701) and control-lines and wherein disk data is stored in track sectors each of which includes a header portion followed by a data portion, characterised in that the bus control lines include a header/data selection signal (HDR/DATA), the disk drive control apparatus (121) causes codes read from disk to be passed to the controller (107) on the data transfer lines (701) when the selection signal selects a header and causes codes to pass in a selected direction between the controller and disk when the selection signal selects data, and in that the controller (107) includes means (1919, 1913) for providing data codes to and receiving data codes from the data transfer lines (701), means (1911) for comparing codes received when the selection signal selects a header with an expected header (EHDR), means (1961, 1945) operative when a match occurs to cause the selection signal to switch to selection of data, means (1911, 1965) operative then to count data codes until transfer of data codes to or from the data portion of the sector is complete, and means (1911, 1961, 1945) thereupon operative to switch the selection signal back to header and to determine a new expected header (EHDR).
Claim 2
Dependent Claim
226 words
A disk drive system comprising a controller (107) connected to control apparatus (121) of at least one disk drive (119) by a bus (127) including data transfer lines (701) and control-lines and wherein disk data is stored in track sectors each of which includes a header portion followed by a data portion, characterised in that the bus control lines include a header/data selection signal (HDR/DATA), the disk drive control apparatus (121) causes codes read from disk to be passed to the controller (107) on the data transfer lines (701) when the selection signal selects a header and causes codes to pass in a selected direction between the controller and disk when the selection signal selects data, and in that the controller (107) includes means (1919, 1913) for providing data codes to and receiving data codes from the data transfer lines (701), means (1911) for comparing codes received when the selection signal selects a header with an expected header (EHDR), means (1961, 1945) operative when a match occurs to cause the selection signal to switch to selection of data, means (1911, 1965) operative then to count data codes until transfer of data codes to or from the data portion of the sector is complete, and means (1911, 1961, 1945) thereupon operative to switch the selection signal back to header and to determine a new expected header (EHDR).
Claim 3
Dependent Claim
99 words
A system according to claim 1, characterised in that the control lines further include a command/data mode signal (C/D MD SEL) selecting between transfer of command codes from the controller (107) to the control apparatus (121) and transfer of data between the controller and disk, in that the controller continues to respond alternately to header and data selection by the selection signal (HDR/DATA) while the mode signal selects data mode, and by means (1911, 1967) operative to count sectors read or written until transfer of data is complete and thereupon to switch the mode signal to select command mode.
Claim 4
Dependent Claim
40 words
A system according to claim 2, characterised in that the control lines of the bus (127) include control instruction lines (705) for transferring control instructions from internal control means (1901, 1909) of the controller (107) to the control apparatus (121).
Claim 5
Dependent Claim
47 words
A system according to claim 3, characterised in that the control instructions include an immediate status instruction and in that the control apparatus (121) includes means responsive to such an instruction to transfer an immediate status code to the controller (107) on the data transfer lines (701).
Claim 6
Dependent Claim
70 words
A system according to claim 4, characterised in that the control lines of the bus (127) include an interrupt line (e.g. 715) for passing an interrupt signal (INT1) to the controller from the control apparatus (121) which includes means (PLA 1601, 1605) for setting the interrupt signal in response to an internal disk drive interrupt signal (SI) and for clearing the interrupt signal in response to an immediate status instruction.
Claim 7
Dependent Claim
257 words
A system according to claim 5, characterised in that the internal control means (1901, 1909) is connected to the means (1919, 1921, 1913) for providing the data codes to and receiving the data codes from the data transfer lines, the internal control means provides a microinstruction for controlling operation of the said means for providing and receiving the data codes and of means (1988) providing the mode signal (C/D MD SEL), in that the control instructions include an initiate sequence instruction, in that the internal control means provide operational instructions for controlling operations of the disk drive to the means for providing and receiving the data codes together with the initiate sequence instruction on the control instruction lines (705), the means for providing the mode signal responds to the microinstruction by providing a command mode signal on the command data mode line (C/D MD SEL) while the internal control means is providing the operational instructions to the data transfer lines, the disk drive control apparatus (121) includes internal disk control means (609) connected to data transfer means (611) for controlling the data transfer means in response to the operational instructions, the data transfer means is connected to control instruction receiving means (609), the control instruction receiving means provides an initiate sequence signal to data transfer means in response to said initiate sequence instruction, and the data transfer means responds to the command transfer signal and the initiate sequence signal by transferring the operational instructions from the data transfer lines (701) to the internal disk control means (611).
Claim 8
Dependent Claim
136 words
A system according to claim 6, characterised in that the operational instructions include a new block instruction specifying a read cperation reading data codes from disk or a write operation writing data codes to disk, the internal disk control means (609) responds to the new block instruction by (a) preparing the disk drive (125) to perform the read operation or the write operation and (b) providing one of the internal interrupt signals to said control instruction receiving means, the internal controller control means responds to said interrupt signal produced in response to said internal interrupt signal produced by said internal disk control means in response to said new block operational instruction by providing another said microinstruction and the means for providing the data transfer signal responds to this other microinstruction by providing the data transfer signal.
Claim 9
Dependent Claim
125 words
8 . A system according to claim 7., characterised in that the bus (127) connects the controller (127) to a plurality of disk drives (119(0)etc), the bus further comprises device selection lines (DEVSELECT1,2) for device selection codes from the controller specifying one of the disk drives, and a plurality of interrupt lines (715, 717, 719, 721) corresponding to the disk drives respectively, said interrupt signal receiving means is connected to said plurality of interrupt signal buses; the internal control means (1901, 1909) provides the device selection codes to the device selection lines and receives the interrupt signals on the interrupt lines, and the control apparatus (121) of each disk drive responds to control instructions only when the device selection code specifies of that disk drive.
Claim 10
Dependent Claim
108 words
9• A system according to claim 8, characterised in that the bus further comprises a disk storeback line (713) for providing a signal (DISK STB/ACK) from disk drive (125) to the controller (107) specifying that the data transfer lines (701) are transferring data codes from the disk drive to the controller, a controller storeback line (711) for providing a signal (CON STB/ACK) from the controller to the disk drive specifying that the data transfer lines are transferring data codes from the controller to the disk drive and a parity bus (703) for providing parity codes for the data codes transferred from the controller or from the disk drive.
Claim 11
Dependent Claim
109 words
A system according to claim 9, characterised in that the plurality of disk drives (119) includes up to four disk drives; the data transfer lines (701) transfer 8 bits of the data codes and operational instructions in parallel; the parity bus (703) transfers a one-bit parity code; the control instruction lines (705) transfer three bits of control instruction in parallel; the device selection lines (707, 709) transfer two bits of device code in parallel; and the controller storeback bus (711), the disk storeback bus (713), the interrupt lines (715, 717, 719, 721), the command/data mode line (723) and the header/data selection line (725) each transfer a one bit signal.
References Cited (Backward Citations)
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