EP0509637A2
Expired / Lapsed
EP
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Magnetic tape storage apparatus
Assignee: Fujitsu Ltd
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Filing: 1992-03-12
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Granted: —
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Expires: 2012-03-12
Abstract
Abstract A storage apparatus which performs writing and reading of data on a magnetic tape by the helical scan method using a rotary head, in particular one suited to use with a large-sized host computer, which storage apparatus includes mainly a storage control unit connected to the host computer and a drive unit for reading from and writing on the magnetic tape. System areas are formed on the magnetic tapes, which system areas have tables which include management information relating to the magnetic tapes themselves and able to be renewed by the storage control unit. By using these tables, the magnetic tapes can be easily accessed at a high speed, diagnosed as to trouble, and managed in data blocks.
Inventors
- 👤 Junichi c/o Fujitsu Limited Yoshioka
- 👤 Daijiro Okihara
- 👤 Takashi Watanabe
- 👤 Jun Takayama
- 👤 Takeshi Ninomiya
- 👤 Shinji Hamada
- 👤 Chiaki Yamauchi
- 👤 Madoka Ichikawa
- 👤 Akihiro Iseno
- 👤 Toshiya Nakajima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 16:34
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/06; G06F3/0601; G11; G11B; G11B20/00; G11B20/10; G11B20/12; G11B20/1201; G11B20/1207; G11B20/1209; G11B27/00; G11B27/10; G11B27/102; G11B27/107; G11B27/11; G11B27/19; G11B27/28; G11B27/32; G11B27/327; G11B27/328; G11B27/36; G06F3/0668; G06F3/0671; G06F3/0673; G06F3/0682; G11B20/1211; G11B2220/00; G11B2220/60; G11B2220/65; G11B2220/90
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
225 words
A magnetic tape storage apparatus comprised of a drive unit (2) for writing/reading information on and from a magnetic tape (1) using a rotary head (RH) by the helical scan method and a storage control unit (3) for controlling the drive unit (2), said magnetic tape storage apparatus characterized by having a system area (7) which is formed at a portion of the magnetic tape (1) other then the user area (8) where the user data is recorded and which can be used only by the storage control unit (3); a table read-out means (4) which reads out management information tables relating to the magnetic tape itself, written in the system area (7), into a memory means (5) in the storage control unit (3) when the magnetic tape (1) is loaded into the drive unit (2); and a table record means (6) which, while the storage control unit (3) refers to the data of the read management information table, performs a write/read operation on the user area (8) on the magnetic tape (1), simultaneously renews the data of the management information table in the memory means (5), and finally, when the magnetic tape (1) is unloaded from the drive unit (2), writes the management information tables in the memory means (5), having the renewed data, into the system area (7) of the magnetic tape (1).
Claim 2
Dependent Claim
53 words
An apparatus as set forth in claim 1, wherein said table record means (6) is operative to write in the said system area (7) said management information tables showing the correspondence relationship of the position information on the magnetic tape (1) and the division information of the data on the magnetic tape (1).
Claim 3
Dependent Claim
192 words
An apparatus as set forth in claim 2, wherein said table record means (6) is operative to prepare a table (13) of correspondence of the logical numbers of the data blocks and tape marks (12) on the magnetic tape (1), the physical numbers showing the physical positions of the data blocks and tape marks (12) on the magnetic tape, and flag information showing if the data blocks are tape marks (12) and to write the same on the magnetic tape (1), said tape read-out means (4) is operative to read the table (13) recorded on the magnetic tape (1) into the storage control unit (3), and provision is further made of a high speed positioning means (11) which, in positioning to a data block or tape mark (12) corresponding to any logical number, refers to the table read into the storage control unit (3) by the table read-out means (4), obtains the physical number of the target data block or tape mark (12) on the magnetic tape from said logical number, tape mark (12), or flag information, and positions at a high speed to the target data block or tape mark (12).
Claim 4
Dependent Claim
40 words
An apparatus as set forth in claim 1, wherein said high speed positioning means (11) positions to a target block by positioning at a high speed to just before the target data block and then switching to the usual speed.
Claim 5
Dependent Claim
126 words
An apparatus as set forth in claim 1, wherein further provision is made of: a flag recording means for setting a management flag showing renewal of the table (13) and recording it in the area of the table management block (14) following the table recording area on the magnetic tape (1) upon unloading, a resetting means for resetting the management flag of the table management block (13) upon loading of the magnetic tape (1), and a flag judgement means for judging that the table has been renewed normally during the previous unloading if the management flag has been in the set state before the resetting by the resetting means and for judging that the table has been renewed normally when the management flag has been reset.
Claim 6
Dependent Claim
179 words
An apparatus as set forth in claim 2, wherein said table record means (6) is operative to prepare a table (13) of correspondence of the logical numbers of the tape marks (12) showing the end positions of the data files on a magnetic tape (1) comprised of one or more data blocks and the physical numbers showing the physical positions of the tape marks (12) on the magnetic tape and to write the same on the magnetic tape (1), said tape read-out means (4) is operative to read the table (13) recorded on the magnetic tape (1) into the storage control unit (3), and provision is further made of a high speed positioning means (11) which, in positioning to any tape mark (12), refers to the table (13) read out by the table read-out means (4), obtains the physical number on the magnetic tape (1) corresponding to the logical number of the tape mark (12) closest to the target data block, positions to the tape mark (12), then switches to normal speed and positions to the target data block.
Claim 7
Dependent Claim
86 words
An apparatus as set forth in claim 6, wherein said table read-out means (4) reads into the memory means (5) the said table (13) during loading of the magnetic tape (1) and said table record means (6) renews the table (13) in the memory means in accordance with the access of the magnetic tape (1) and also writes in the magnetic tape (1) the table (13) in the memory means or adds just the changes of the table (13) during unloading of the magnetic tape (1).
Claim 8
Dependent Claim
126 words
An apparatus as set forth in claim 6, wherein further provision is made of: a flag recording means for setting a management flag showing renewal of the table (13) and recording it in the area of the table management block (14) following the table recording area on the magnetic tape (1) upon unloading, a resetting means for resetting the management flag of the table management block (13) upon loading of the magnetic tape (1), and a flag judgement means for judging that the table has been renewed normally during the previous unloading if the management flag has been in the set state before the resetting by the resetting means and for judging that the table has been renewed normally when the management flag has been reset.
Claim 9
Dependent Claim
47 words
An apparatus as set forth in claim 1, wherein said table recording means (6) is operative to write in the management information table (53) of the magnetic tape (1) the information of the head position and end position of the area where user data was effectively written.
Claim 10
Dependent Claim
64 words
An apparatus as set forth in claim 9, wherein provision is made of an access means (51) which refers to the head position and end position of the user data, obtained from the said table (53) of the magnetic tape (1), and which performs a write or read operation using as a valid area the area from the head position to the end position.
Claim 11
Dependent Claim
54 words
An apparatus as set forth in claim 10, wherein said table recording means (6) records in the table (53) of the magnetic tape (1) the physical position information of the head data block and the physical position information of the end data block of the user data validly written on the magnetic tape (1).
Claim 12
Dependent Claim
57 words
An apparatus as set forth in claim 11, wherein the said table record means (6) records in the table (53) of the magnetic tape (1) the physical position information of the head tape mark (12-1) and the physical position information of the end tape mark (12-n) of the user data effectively written on the magnetic tape (1).
Claim 13
Dependent Claim
61 words
An apparatus as set forth in claim 9, wherein when performing writing of data at the head position of the user data and the write operation terminates abnormally at that writing position, said table record means (6) performs the write operation on the next position and records as the head position the position where the writing could first be performed effectively.
Claim 14
Dependent Claim
36 words
An apparatus as set forth in claim 10, wherein said access means (51) invalidates a read request received for a position over the end position of the user data effectively written on the magnetic tape (1).
Claim 15
Dependent Claim
24 words
An apparatus as set forth in claim 1, wherein provision is made of a system area set-up means (61) for setting the system area.
Claim 16
Dependent Claim
40 words
An apparatus as set forth in claim 15, wherein said system area set-up means (61) sets the system area (7) between the physical beginning of tape and the logical beginning of tape at the head of the magnetic tape (1).
Claim 17
Dependent Claim
43 words
An apparatus as set forth in claim 16, wherein said table record means (6) records in the said system area (7) the hardware version and microprogram version of the units (2, 3) and the number of times of use of the magnetic tape.
Claim 18
Dependent Claim
53 words
An apparatus as set forth in claim 16, wherein the said table record means (6) reads the number of times of use of the tape from the system area (7) of the said magnetic tape upon execution of an unload command, increments it by one, then records it in the system area (7).
Claim 19
Dependent Claim
38 words
An apparatus as set forth in claim 1, wherein said table record means (6) writes in the management information table (63) of the magnetic tape (1) status information showing if there is an abnormality in the magnetic tape.
Claim 20
Dependent Claim
112 words
An apparatus as set forth in claim 19, wherein provision is made of an error detection means (71) which detects tape abnormalities from the abnormal termination of the writing or reading of the magnetic tape (1) and a status information generating means (72) which prepares status information showing the presence of a tape abnormality based on the results of detection by said error detection means (71) and wherein said table record means (6) writes in the management information table (63) the status information upon unloading and is provided with a judgement means for judging the presence of a tape abnormality by reading status information recorded on the magnetic tape (1) upon loading.
Claim 21
Dependent Claim
81 words
An apparatus as set forth in claim 19, wherein said table record means (6) is operative to make a status report showing the tape abnormality to the host computer when a predetermined number of tape abnormalities have been detected or when the end of the magnetic tape has been reached and record on the magnetic tape (1) the status information upon unloading of the tape upon a tape unloading command made from the host computer in accordance with the status report.
Claim 22
Dependent Claim
31 words
An apparatus as set forth in claim 20, wherein write and read operations on the magnetic tape (1) are prohibited when said judgement means (74) judges there is a tape abnormality.
Claim 23
Dependent Claim
65 words
An apparatus as set forth in claim 20, wherein said status information generating means (72) prepares status information including the position information of the magnetic tape (1) where the tape abnormality was detected and wherein said judgement means (74) validates writing and reading of the user data at data blocks other than the data block where the tape abnormality occurred, obtained from the status information.
Claim 24
Dependent Claim
93 words
An apparatus as set forth in claim 1, wherein said table record means (6) is operative to record in a plurality of positions (A, A2, A3) of the magnetic tape (1) the said management information table and wherein said table read-out means (4) is operative to read the management information table recorded at a specific position (A) in the system area (7) on the magnetic tape (1) and, when the management information table of the specific position (A) cannot be normally read, read the management information table of the other positions (A2, A3).
Claim 25
Dependent Claim
66 words
An apparatus as set forth in claim 24, wherein said table record means (6) records flag information (L) showing that the management information table has been renewed when recording the management information table on the magnetic tape (1) and wherein said table read-out means (4) detects renewal using the flag information and performs corresponding processing when reading the management information table from the magnetic tape (1).
Claim 26
Dependent Claim
102 words
An apparatus as set forth in claim 24, wherein said table record means (6) records the management information table in a first position (A) between the physical beginning of tape (physical BOT) of the head of the magnetic tape (1) and the logical beginning of tape (logical BOT) of the user area (8), records, for the user area (8), the management information table in a second position (A2) following the position where the writing of the data file ends, and records the management information table at a third position (A3) before the physical end of tape (physical EOT) of the magnetic tape.
Claim 27
Dependent Claim
80 words
An apparatus as set forth in claim 26, wherein, when writing new data in a state with the management information table recorded at the second position (A2) following the position of the end of writing of the data file, the said table record means (6) writes a new data file over the management information table of the second position (A2), then records the management information table at the second position (A2′) following the end position of the new data file.
Claim 28
Dependent Claim
65 words
An apparatus as set forth in claim 24, wherein the said table record means (6) writes the management information table opened in the memory means (5) of the storage control unit (3) over the management information tables of the number of locations (A, A2, A3) already recorded on the magnetic tape (1) to renew the same when receiving an unload command from the host computer.
Claim 29
Dependent Claim
209 words
An apparatus as set forth in claim 1, wherein said storage control unit (3) has inside it a data buffer (22), is constituted so that it stores in the data buffer (22) data transferred from the host computer, then transfers it to the drive unit (2) and writes it on the magnetic tape (1) and, on the other hand, transfers data read from the magnetic tape (1) from the drive unit (2) to the data buffer (22) for storage, then transfers it to the host computer, and further is provided with: a tape mark generation means (92) which generates an odd number of tape marks (12) and writes them at the end of the file if the file is the final one and generates an even number of tape marks and writes them at the end of the file if the file is the final one when performing write processing of a file on the magnetic tape (1) and a tape mark detection means (93) which deems detection of an odd number of tape marks (12) as one mark and judges there is a file division and deems detection of an even number of tape marks (12) as two marks and judges that the file is the final one.
Claim 30
Dependent Claim
121 words
An apparatus as set forth in claim 29, wherein said tape mark generating means (92) is operative to generate three tape marks and write them at the end of the file if the file is not the final one and to generate two tape marks and write them at the end of the file if the file is the final one when performing write processing of a file on the magnetic tape (1) and said tape mark detection means (93) is operative to deem the three tape marks as one and judge that there is a file division and to judge the file is a final one with two tape marks (12) when performing reading processing of a magnetic tape (1).
Claim 31
Dependent Claim
45 words
An apparatus as set forth in claim 29, wherein said tape mark generation means (92) writes a further tape mark after an even number of already written tape marks to make an odd number of marks when writing a new file after a final file.
Claim 32
Dependent Claim
41 words
An apparatus as set forth in claim 31, wherein said tape mark generation means (92) writes a further tape mark (12) after two already written tape marks (12) to make three marks when writing a new file after a final file.
Claim 33
Dependent Claim
176 words
An apparatus as set forth in claim 1, wherein said storage control unit (3) has inside it a data buffer (22), is constituted so that it stores in the data buffer (22) data transferred from the host computer, then transfers it to the drive unit (2) and writes it on the magnetic tape (1) and, on the other hand, transfers data read from the magnetic tape (1) from the drive unit (2) to the data buffer (22) for storage, then transfers it to the host computer, and further is provided with: a dummy data writing means (130) which transfers dummy data to the drive unit (2) and writes it on the magnetic tape (1) when the data buffer (2) temporarily becomes empty during the transfer of data from the data buffer (22) to the drive unit (2) during writing and a dummy data delete means (14) which prohibits the transfer of the dummy data to the data buffer (22) when dummy data is detected from the readout data transferred from the drive unit (2) during reading.
Claim 34
Dependent Claim
59 words
An apparatus as set forth in claim 1, wherein said dummy data writing means (130) is operative to add an identification code showing that the data is valid to the head of the transferred data from the data buffer (22) and to add an identification code showing that the data is dummy data to the head of dummy data.
Claim 35
Dependent Claim
68 words
An apparatus as set forth in claim 34, wherein said dummy data delete means (140) is operative to detect an identification code from the read-out data transferred from the drive unit (2), transfer the transferred data to the data buffer (22) if the identification code shows valid data, and prohibit the transfer of the transferred data to the data buffer (22) when the identification code shows dummy data.
Claim 36
Dependent Claim
53 words
An apparatus as set forth in claim 33, wherein the dummy data write means (130) is operative to add dummy data for a predetermined certain amount of time to the end of data transferred from the data buffer (22) when a notification of end of data transfer is received from the host computer.
Claim 37
Dependent Claim
51 words
An apparatus as set forth in claim 35, wherein said dummy data delete means (140), when recognizing dummy data, is operative to recognize the end of transfer of read-out data and notify the same to the host computer when the dummy data has continued for a predetermined certain amount of time.
References Cited (Backward Citations)
No citation records indexed.
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