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Browse Prior Art Database

Emulated Keylock for 5080 Tablet

IP.com Disclosure Number: IPCOM000035728D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 7 page(s) / 307K

Publishing Venue

IBM

Related People

Marks, L: AUTHOR [+4]

Abstract

A nonvolatile random-access memory (NVRAM) connected to a 5085 control unit may be used to provide an output signal produced by a unique series of key-presses on the 5080 graphics puck which signal places the 5085 control unit (C/U) in an operating state. The unit is locked in an inoperative state until this unique password has been entered.

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Emulated Keylock for 5080 Tablet

A nonvolatile random-access memory (NVRAM) connected to a 5085 control unit may be used to provide an output signal produced by a unique series of key- presses on the 5080 graphics puck which signal places the 5085 control unit (C/U) in an operating state. The unit is locked in an inoperative state until this unique password has been entered.

This simple security system may be operated as follows. Following power-on, the control unit tests the status of the keylock. If the emulated keylock is in the secure or locked state, the code prevents IPL of the C/U and waits for a change in the keylock state. A master password is loaded into NVRAM during system manufacture. The customer may change this password. The hardware which reads the nonvolatile storage, as well as the code that checks the keylock state, resides in the 5085 control unit. A message on the 5080 screen informs the user that the system is locked.

The NVRAM enhances system security by reducing the possibility of defeating traditional keylock switches. The NVRAM need not prevent IPL of the C/U; it can just blank the video, and prohibit user input. This makes powering on the system easier and also permits the user to re- lock the unit mid-task and leave the terminal area. More generally, this technique pertains to systems which use computers as front-end processors (FEPs), and more particularly to systems which have a need for controlled access. On many systems, the keyboard and mouse are connected to the main computer through a FEP, which is responsible for bringing up the larger computer. In addition, the small FEP is responsible for catching realtime keyboard and mouse action. This small front- end computer's hardware is separate from the large computer. The present system takes advantage of the separation of the front end processor and computer and uses it as a basis for secured access to the large computer.

The figure shows a typical 5080 graphics system set-up. It contains a keyboard, terminal, controller, and tablet. The puck is attached to the tablet. The terminal and keyboard are in t...