Method and apparatus for accessing data recorded as linked lists

Claim 3

The method set forth in claim 1 wherein the number of storage areas in each group is a constant predetermined number and each successive last storage area of the respective groups is addressed from an immediately preceding group by adding the constant predetermined number to the contents of the forward pointer in the last area of the immediately preceding group and using the sum of such addition as the address of the next area to be accessed.

Claim 4

The method set forth in claim 1 in which each last storage area of each of the groups in a continuation chain, has a recording of an address pointer to a first area of a next succeeding group of the chain and an indication of the number of areas is said next succeeding group.

Claim 5

The method set forth in claim 1 comprising generating and storing an indication of the number of storage areas for all of the groups in the chain; storing an address pointer to a next area in each of the storage areas in the chain; and adding the said number to the address pointer of each last area of the respective groups and addressing a last area of the immediately succeeding group using the added sum as the address.

Claim 7

The method set forth in claim 5, wherein the recorded record member is a write-once read many data storing disk having a multiplicity of concentric tracks, each track having a predetermined number of addressable sectors, and each of said areas is constituted one of said sectors; and said groups have either an integral multiple or sub-multiple of the number of the sectors in said concentric tracks.

Claim 8

Data storage apparatus for accessing data from a data storage means in which the data has been recorded as a linked list, the data storage means having chained data storage area in which teach storage area has a forward pointer to the next in the chain, the chain being subdivided into predefined groups of storage areas, the apparatus comprising means operable, in a first phase of an access operation, to search through the last storage area only of each group along the chain of storage areas on the data storage means to identify the first group of which the last data storage area contains no data, and further means operable, in a second phase of an access operation, to read serially through the storage areas of the group identified in the first phase to find where the last recorded storage area is in the chain.

Claim 9

Data storage apparatus for accessing data from a data storage means in which the data has been recorded as a linked list, the data storage means having chained data storage area in which teach storage area has a forward pointer to the next in the chain, the chain being subdivided into predefined groups of storage areas, the apparatus comprising means operable, in a first phase of an access operation, to search through the last storage area only of each group along the chain of storage areas on the data storage means to identify the first group of which the last data storage area contains no data, and further means operable, in a second phase of an access operation, to read serially through the storage areas of the group identified in the first phase to find where the last recorded storage area is in the chain.

Claim 10

A data storing system having a record member storing data in a plurality of continuation chains and a directory means on the record member indicating a first entry point of the respective continuation chains, each of the chains including a number of addressable data storing areas of the record member which are addressably linked by address pointers, the areas being arranged in serially linked groups of the areas, the areas in a group being contiguous on the media, each of the groups having a first and last one of the areas which are serially linked beginning at the first one and ending at the last one of the areas and the last one of the areas having an address pointer to a first one of the areas in another one of the groups in the continuation chain, the system including, in combination: computer means operatively coupled to the record member for reading data stored on the record member, the computer means having data accessing program indicia for enabling the computer means to read a last one of the addressable areas in successive ones of said groups until finding a last one of such addressable areas that contains no data in a predetermined one of the groups; and indicate program indicia in the data accessing program indicia for enabling the computer means to indicate that the addressable data having the highest number of intervening addressable areas to the single starting point is in the predetermined one of the groups.

Claim 11

A data storing system having a record member storing data in a plurality of continuation chains and a directory means on the record member indicating a first entry point of the respective continuation chains, each of the chains including a number of addressable data storing areas of the record member which are addressably linked by address pointers, the areas being arranged in serially linked groups of the areas, the areas in a group being contiguous on the media, each of the groups having a first and last one of the areas which are serially linked beginning at the first one and ending at the last one of the areas and the last one of the areas having an address pointer to a first one of the areas in another one of the groups in the continuation chain, the system including, in combination: computer means operatively coupled to the record member for reading data stored on the record member, the computer means having data accessing program indicia for enabling the computer means to read a last one of the addressable areas in successive ones of said groups until finding a last one of such addressable areas that contains no data in a predetermined one of the groups; and indicate program indicia in the data accessing program indicia for enabling the computer means to indicate that the addressable data having the highest number of intervening addressable areas to the single starting point is in the predetermined one of the groups.

Claim 12

The system of claim 8, further including, in combination: said data accessing program indicia further having scan program indicia for enabling the computer means to operate after the indicate program indicia were executed to serially read the areas in the predetermined one of the groups beginning with a predetermined one of the areas and proceeding through the linking toward the last one of the areas in the predetermined one of the groups, and to detect that a given one of the areas in the predetermined one of the groups contains no data, then to stop further reading and indicating that the area in the predetermined one of the groups immediately preceding said given one of the areas in the linking contains the data in the area having the most number of interven ing areas to the predetermined one of the areas.

Claim 13

The system of in claim 9, further including, in combination: random access storage means in the computer means for receiving and storing data from the areas being read; the data accessing program indicia including analysis indicia for enabling the computer means to analyse the data stored in the random access storage means for identifying the last data in a continuation chain.