Abstract: A typewriter may store a document in a first format with margins and tab stop locations defined for a first format and then the operator may change the margin or tabs to a second format. The operator may also select whether the tab stop locations may be played out with the same relative positioning to the left margin or be played out using the newly set tabs and margin setting. The newly set tab stop locations are defined as a fixed position relative to the print line and are independent of the left margin position or the position of the original tab stop location relative to the left margin.The memory of the typewriter may be optionally updated when the document is played out using the second format tab stop locations, if the operator conditions the storage to accept changes during playout. Alternatively, the document may be played out using the second format tab stop locations, and the original format tab stop locations are maintained for future use.

Abstract: A computer system with provision for inserting/removing memory cartridges is improved by inhibiting erroneous operation as a result of noise produced on insertion/removal of a memory cartridge. Removable cartridges are connected/disconnected from a cartridge bus which is distinct from the system bus to which all other components are coupled. A controlled isolation is provided between the two buses. An idler routine ensures that in the absence of operator requested tasks the isolation prevents noise on the cartridge bus from reaching the system bus. When the processor executes an instruction (or only selected instructions) the isolation is disabled so that data/instructions can flow to/from the system and cartridge bus.