Disk memory system

Claim 2

A disk memory system comprising: transducer means for reading and writing information on a disk; at least one disc medium having a plurality of concen­tric tracks each of which is divided into plural data sectors and plural servo zones therebetween, each of said data sectors having identification infor­mation which is prerecorded and only read by said transducer means, and data information and error correction information both of which are recorded and read by said transducer means together, each of said servo zones having servo information which is prerecorded and only read by said transducer means, each of said data sectors being further divided into plural sub-data sectors into which said data information and error correction information are distributed, and additional servo zones being provided between adjacent sub-data sectors which are selected from said sub-data sectors and having additional servo information therein which is prere­corded and only read by said transducer means; spindle motor means for rotating said disc medium at a predetermined angular velocity; positioning means for positioning said transducer means on a selected one of said concentric tracks; and positioning control means for receiving said servo information and said additional servo information read by said transducer means and for controlling said positioning means so that said transducer means is positioned precisely on said se­ lected one of said concentric tracks.

Claim 3

A disk memory system as claimed in claim 1, in which said servo information and additional servo information are identical.

Claim 4

A disk memory system as claimed in claim 1, in which each of said data sectors is divided into two sub data sectors one of which includes the whole of said identification informa­tion and a part of said data information, and the other of which includes the remaining part of said data information and the whole of said error correction information.

Claim 5

A disk memory system as claimed in claim 1, in which said transducer means encounters said servo zones and said addi­tional servo zones at a constant frequency.

Claim 6

A disk memory system as claimed in claim 1, in which said identification information includes information on relative positions of said additional servo zones in each of said data sectors.

Claim 7

A disk memory system comprising: transducer means for reading and writing information on a disc; at least one disk medium having a plurality of concen­trically and radially displaced areas each of which has a plural­ity of concentric tracks, data transfer rates for said areas being selected in accordance with radial offset from the center of said disk medium, each of said concentric data tracks being divided into plural data sectors and plural servo zones therebetween, said concentric data tracks for each of said area being divided into said data sectors different in number and said servo zones therebetween, each of said data sectors having identification infor­mation which is prerecorded and only read by said transducer means, and data information and error correction information both of which are recorded and read by said transducer means together, each of said servo zones having servo information which is prerecorded and only read by said transducer means, each of said data sectors being further divided into plural sub-data sectors into which said data information and error correction information are distributed, additional servo zones being provided between said sub-data sectors and having additional servo information therein which is prerecorded and only read by said transducer means; said data sectors for each area being divided into said sub-data sectors different in number in such a manner that positions of said servo zones and additional servo zones are radially aligned throughout said areas; spindle motor means for rotating said disc medium at a predetermined angular velocity; positioning means for positioning said transducer means on a selected one of said concentric tracks; and positioning control means for receiving said servo information and said additional servo information read by said transducer means and for controlling said positioning means so that said transducer means is positioned precisely on said se­ lected one of said concentric tracks.

Claim 8

A disk memory system comprising: transducer means for reading and writing information on a disc; at least one disk medium having a plurality of concen­trically and radially displaced areas each of which has a plural­ity of concentric tracks, data transfer rates for said areas being selected in accordance with radial offset from the center of said disk medium, each of said concentric data tracks being divided into plural data sectors and plural servo zones therebetween, said concentric data tracks for each of said area being divided into said data sectors different in number and said servo zones therebetween, each of said data sectors having identification infor­mation which is prerecorded and only read by said transducer means, and data information and error correction information both of which are recorded and read by said transducer means together, each of said servo zones having servo information which is prerecorded and only read by said transducer means, each of said data sectors being further divided into plural sub-data sectors into which said data information and error correction information are distributed, additional servo zones being provided between said sub-data sectors and having additional servo information therein which is prerecorded and only read by said transducer means; said data sectors for each area being divided into said sub-data sectors different in number in such a manner that positions of said servo zones and additional servo zones are radially aligned throughout said areas; spindle motor means for rotating said disc medium at a predetermined angular velocity; positioning means for positioning said transducer means on a selected one of said concentric tracks; and positioning control means for receiving said servo information and said additional servo information read by said transducer means and for controlling said positioning means so that said transducer means is positioned precisely on said se­ lected one of said concentric tracks.