28. Glossary
 

APPLICATION             A program set up according to the appropriate machine
                        conventions. The program is blown into ROM or EPROM
                        cards using static data structures that identify the
                        hotkey to activate it, menu and help pages for
                        commands.

BANK                    16K chunk of memory, always on a 16K boundary in the
                        logical address space. See also SEGMENT.

BLINK                   The name given to the Z88's gate array chip. The chip
                        handles the screen, serial port, keyboard, memory
                        switching, interrupts, etc.

CARD MANAGER            This refers to the code which deals with inserting and
                        removing ROM cards. The basic rules are that all
                        interchange should be done from the INDEX and that the
                        machine is switched ON. If an application is using a
                        ROM card then the card's slot number is displayed in
                        the column next to the application name in the INDEX
                        popdown window. RAM cards can only be inserted, never
                        removed. File EPROM cards can be inserted and removed
                        at most time, but obviously not while the FILER is
                        actively reading or writing slot 3.

CLI                     Command Line Interpreter. This is used to simulate the
                        keyboard and to rebind streams (re-direct or copy I/O
                        information).

DIRECTOR                synomym for INDEX (the name used for it while much of
                        the code was being written, hence DC operating
                        system calls, not IC calls).

DOR                     node in dynamic tree structure used in applications and
                        in the RAM filing system.

EXPLICIT FILENAME       A filename which includes the device and root
                        directories. For example "queries.pip" might become
                        ":RAM.1/office.dir/queries.pip".

EXTENSION               Up to three letters after the filename, usually used to
                        classify the file, eg. you might add .pip to all your
                        PipeDream files to aid identification.

FILTER                  Conceptual 'object' (actually a set of routines) which
                        perform transformations in a byte sequense, Also see
                        Printer Filter.

HANDLE                  A handle is a 16bit value, usually returned in the IX
                        register, used in file-like operations (eg. files,
                        filters, etc.) to direct input and output. For example,
                        a handle is returned when a file is opened and is
                        subsequently used whenever the file is accessed. A file
                        can have several handles associated with it and
                        attributes like the sequential pointer into a file are
                        associated with each handle and not with the file
                        itself. There are a finite number of handles in the
                        machine, initially around 150, and the current number
                        available is reflected in the high word of the
                        sequential pointer associated with a handle value of -1
                        (In BASIC, PTR#-1).

INSTANTIATION           This refers to one 'run' of an application. For example
                        if two copies of PipeDream are current, than each copy
                        is called an 'instantiation' and although the same
                        program is running, the data associated with each are
                        independent.

LOGICAL ADDRESS         Address which the Z80 CPU 'sees', ie. a standard 16bit
                        Z80 address. See also PHYSICAL ADDRESS.

MOS                     Machine operating system. Also referred to as OZ.

PAGE                    256 byte chunk of memory, on a 256-byte boundary. This
                        is the basic unit of memory on which the allocation
                        routines operate.

PHYSICAL ADDRESS        24 byte address referring to an actual memory location
                        (only 22bits are significant, giving an addressing
                        range of 4MB). The memory are organised, seen in 256
                        16K blocks, each slot addressing 1MB, giving a total of
                        4MB (14bit logical address + 8bit bank number = 22 bit)

PRE-EMPTION             The suspension of a process, normally prior to the main
                        body of a system call.

PRINTER FILTER          This is a filter controlled by the Printer Editor. It
                        allows applications to use special printing effects by
                        specifying filter codes and letting the filter generate
                        codes appropriate to the printer actually in use.

PROCESS                 A particular instantiation of a program (normally an
                        application).

SEGMENT                 1) One of the four 16K portions of the logical memory
                        map (which the Z80 can see). All memory banks in the
                        system can be bound to one of the four memory segments
                        (64K/4 = 16K, hence four segments).

                        2) One of the portions of a filename separated by '/',
                        ie. a file or a directory name.

SLOT                    1) One of the three physical holes in the front of the
                        machine, which can accept a RAM, EPROM or ROM card. The
                        internal memory of the machine is thought of as Slot 0.

                        2) The transmission form for a character of data in the
                        serial system, ie. the byte to be transmitted plus
                        appropriate start and stop bits.

                        3) Concept used in PipeDream. Roughly approximates to a
                        spreadsheet cell.

STREAM                  This is a communication channel with an associated
                        handle.