§
Luxuse
Patent Intelligence
Sign In
← Back to Patent Explorer
EP0105241A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Computer system for preventing copying of program

Assignee: Toshiba Corp
•
Filing: 1983-09-14
•
Granted: —
•
Expires: 2003-09-14
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A computer system for preventing copying or duplication of a program which has a CPU (2), a ROM (15), a RAM (18), an FDD unit (4), a loader program executed by the CPU (2) for loading the program from the FDD unit (4) to the memory (18), an address selector switch (21), and an FM/MFM modulating circuit (20). The CPU (2) reads the program from the FDD unit (4) to the RAM (18) under the control of a control program stored in the ROM (15), the program being stored in the FDD unit (4) in the MFM mode which does not allow readout of the program by the loader program. The readout program is modified by the FM/MFM modulating circuit (20) in accordance with a machine number unique to the machine and read from the address selector switch (21). The modified program is written in the FDD unit (4) by the FM/MFM modulating circuit (20).

Inventors

  • 👤 Tadashi Kurachi
  • 👤 Shoji Ueda

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-26 14:50
CPC Classifications
G; G06; G06F; G06F21/00; G06F21/10; G06F21/12; G06F21/121; G06F21/125

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 164 words
A computer system having a central processing unit (2), an internal memory (15, 18) and an external storage (4), a program load program executed by said central processing unit (2) so as to load a program from said external storage (4) to said internal memory (18), comprising means (2, 15, 20) for reading the program from said external storage to said internal memory, the program being written by a program supplier in a storage medium in a special storage mode which does not allow readout of the program by the program load program; means (17) for setting a number unique to said computer system; means (2, 15) for modifying the program stored in said internal memory by said reading means in accordance with the number set by said setting means; and means (2, 15, 20) for writing in the storage medium the program modified by said modifying means in a standard storage mode which allows readout of the program by the program load program.
Claim 2
Dependent Claim 164 words
A computer system having a central processing unit (2), an internal memory (15, 18) and an external storage (4), a program load program executed by said central processing unit (2) so as to load a program from said external storage (4) to said internal memory (18), comprising means (2, 15, 20) for reading the program from said external storage to said internal memory, the program being written by a program supplier in a storage medium in a special storage mode which does not allow readout of the program by the program load program; means (17) for setting a number unique to said computer system; means (2, 15) for modifying the program stored in said internal memory by said reading means in accordance with the number set by said setting means; and means (2, 15, 20) for writing in the storage medium the program modified by said modifying means in a standard storage mode which allows readout of the program by the program load program.
Claim 3
Dependent Claim 27 words
A computer system according to claim 1, characterized in that said special storage mode comprises a different modulation mode for writing bit arrays in the storage medium.
Claim 4
Dependent Claim 27 words
A computer system according to claim 1,' characterized in that said special storage mode comprises a different data format for writing the program in the storage medium.
Claim 5
Dependent Claim 19 words
A computer system according to claim 1, characterized in that said setting means comprises an address selector switch (21).
Claim 6
Dependent Claim 19 words
A computer system according to claim 1, characterized in that said setting means comprises a read only memory (15).

References Cited (Backward Citations)

No citation records indexed.

USPTO Annuity & Maintenance Windows

Maintenance schedule is calculated for granted US utility patents.

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag