DISK SYSTEM AND POWER-ON SEQUENCE FOR THE SAME
 Inventors: Yoshihisa Kamo, Musashimurayama;
Hitoshi Kakuta; Atsushi Tanaka, both of Kokubunji; Yosuke Seo, Sagamihara, all of Japan
 Assignee: Hitachi, Ltd., Tokyo, Japan
[ * ] Notice: This patent is subject to a terminal disclaimer.
 Appl. No.: 09/357,372  Filed: Jul. 20, 1999
Related U.S. Application Data
 Continuation of application No. 08/934,201, Sep. 19, 1997, Pat. No. 6,012,124, which is a continuation of application No. 08/472,460, Jun. 7, 1995, Pat. No. 5,673,412, which is a division of application No. 07/725,672, Jul. 3, 1991, abandoned.
 Foreign Application Priority Data
Jul. 13, 1990 [JP] Japan 2-183936
Oct. 1, 1990 [JP] Japan 2-260439
 Int. CI.7 G06F 12/00; G06F 1/26
 U.S. CI 711/114; 713/330; 360/98.01;
360/78.04; 318/277; 318/431
 Field of Search 711/114, 112;
713/330, 300, 320; 714/6, 710, 711, 820; 360/98.01, 78.01, 78.04, 73.03, 901; 318/277,
 References Cited
U.S. PATENT DOCUMENTS
Re. 34,399 10/1993 Garni et al 360/73.03
3,710,214 1/1973 Anderson 318/102
4,233,666 11/1980 Walberg et al. .
5,148,432 9/1992 Gordon et al 714/7
5,227,930 7/1993 Thanos et al 360/78.04
5,239,659 8/1993 Rudeseal et al 714/6
5,246,479 9/1993 Garni et al 360/73.03
5,423,046 6/1995 Nunnelley et al 713/330
5,488,274 1/1996 Satoh 318/101
5,491,593 2/1996 Donaldson 360/73.03
FOREIGN PATENT DOCUMENTS
51-7071 2/1976 Japan . 1-250128 10/1989 Japan .
Primary Examiner—Ario Etienne
Attorney, Agent, or Firm—Beall Law Offices
With respect to the disk drives provided power from a single power source in a disk drive system, start up power is first supplied to a first start-up group of the disks, preferably comprising all of the master disks, with the size of the group being selected so that the required current does not exceed the capacity of the power source. When the disk drives of the first group have substantially reached steady state, start-up is conducted with respect to a second start-up group of the disk drives so that the current required during start-up for the second group and the current required for steady state drive of the first start-up group does not exceed the capacity of the power source. With respect to each start-up group, the number of disk drives is the maximum integer value and decreases or remains the same with respect to subsequent start-up groups. When simultaneously transferring subdivided data in parallel to all of the disk drives of a parity group, respectively, seek operations in such a system are prevented from occurring simultaneously by offsetting the indices on the disks, by varying the seek operation start timing or by varying the head addresses for the start of reading and writing, all within one revolution, but the seek operations are ended at the same time, to reduce peak current requirements of the power source.
17 Claims, 17 Drawing Sheets