General Information 5 interrupt service routine (ISH) - an assembly language routine intended to perform a certain action, or set of actions, when the computer receives a request from an external device. An "active" ISH is one which is currently enabled for a given device. mass storage unit specifier (msus) - a single word corresponding to the BASIC lan- guage mass storage unit specifier as described in either the 9835A/ B Operating and Programming Manual - HP part number 09835-90000 - or the Mass Storage Techniques Manual- HP part number 09835-90070.
An msus has the following struc- ture - Unit HPIB Device Select 15 14 13 12 11 10 9 8 7 6 5 4 3 2 OBit An msus can designate the current default as its mass storage device (meaning it will use the device indicated by the last MASS STORAGE IS statement executed). This is desig- nated by having the msus be all ones (Le., equal to - 1). set aside for it. Though the source module for the object code may no longer be resident in memory, when created, the module was delimited by certain pseudo-instructions (NAM and END) and is referenced by the name given to it by the NAM pseudo-instruction.
object module - a section of assembled code stored in the pa~ticular region of memory octal expression - a numeric expression which, when displayed or printed, appears as an octal (base-8) number. Within arithmetic operations, it has a decimal value (base-l0). Thus, the value 178 will appear as 17 (representing the value 1510), but if arithmetic was performed on it, it would act as if it were 1710. All octal expressions are necessarily integers in the range of 0 to 1777778. source module - a section of assembly language source code beginning with a NAM pseudo-instruction and ending with the END pseudo-instruction. word - two bytes; a group of 16 binary digits (bits).
1 The device type is the ASCII code for the type minus 1008. Number Address Type 1 Code I I I I I L I I I J I I I I I I I I I I I I I I