Module 2.1: System Operation

A comprehensive set of vocabulary flashcards covering basic DOS commands, DEBUG utility instructions, and fundamental Assembly language operations.

DEBUG

An external line-oriented debugger command in operating systems like DOS that acts as an assembler, disassembler, or hex dump program.

CLS

A common Disk Operating System command used to clear the screen.

CD

A common Disk Operating System command used to change the current directory.

DIR

A common Disk Operating System command used to display a directory listing.

COPY

A common Disk Operating System command used to copy files.

DEL

A common Disk Operating System command used to delete files.

REN

A common Disk Operating System command used to rename files.

MD

A common Disk Operating System command used to make a directory.

RD

A common Disk Operating System command used to remove a directory.

Hexadecimal format

The format in which DEBUG displays all program code and data, and the required form for any data entered into memory.

.COM programs

Programs designed to fit inside a single segment of memory with a maximum size of $65,280$ bytes or less.

Offset $00$ through $FF$ hex

The area containing $256$ bytes that DEBUG often uses for internal data, such as the name of the loaded file.

Q (Quit)

A Debug command that finishes the session and exits back to the DOS environment.

H (Hexarithmetic)

A Debug command that shows the sum and difference of two $4$-bit hexadecimal numbers.

R (Register)

A Debug command that displays all registers and their values, shows the next instruction, and permits changing register values.

E (Enter)

A Debug command that enables the user to key in data or machine instructions into memory at a specific location address.

D (Display or Dump)

A Debug command that displays the content of a portion of memory in both hex and ASCII forms starting at a given address.

A (Assemble)

A Debug command that allows the creation of a program in mnemonic or symbolic code and translates source statements into machine code.

T (Trace)

A Debug command that runs the program in single-step mode, displaying new register values and the next instruction to be executed.

G (Go)

A Debug command that runs the program as a whole in memory and displays the output.

U (Unassemble)

A Debug command that lists all instructions contained in the program beginning at a specified address.

N (Name)

A Debug command used to name a program, requiring an eight-character base name and a .COM extension.

W (Write)

A Debug command that saves the program onto disk storage.

DEBUG prompt

Represented by a hyphen (-), it indicates that the software is ready to accept commands.

MOV (Move data)

An instruction that copies and transfers data between two registers or from immediate data to a register.

ADD (Add Data)

An instruction used to calculate the sum of two registers or a register and immediate data, storing the result in the leftmost register.

SUB (Subtract Data)

An instruction used to calculate the difference of two registers or a register and immediate data, storing the result in the leftmost register.

MUL (Multiply Data)

An instruction that multiplies a given register by the AX register and stores the result in AX; overflows beyond $16$ bits are stored in DX.

DIV (Divide Data)

An instruction that divides the AX register by a given register, storing the quotient in AX and the remainder in DX.

INC (Increment by one)

An instruction used to increase the value of a register by $1$.

DEC (Decrement by one)

An instruction used to decrease the value of a register by $1$.

LOOP (Loop Until Complete)

An instruction that controls program execution for a specified count held in the CX register, decrementing CX by $1$ each iteration until it reaches $0$.