TRS-80 DOS - TRSDOS v1.3 - SYS07/SYS Disassembled

Program Overview

SYS7 is the TRSDOS v1.3 overlay that implements the BACKUP and FORMAT utility commands on the TRS-80 Model III. It is loaded into RAM at 4E00H and occupies the range 4E00H–5D71H, with trailing buffer workspace extending to 6300H. The overlay is invoked by SYS6 (the DOS command handler) when the user types FORMAT or BACKUP at the DOS prompt; control enters at BEGIN (57A1H), which parses the command line, selects between the BACKUP and FORMAT paths, prompts for source and destination drives as needed, and then dispatches to either BACKP (5739H) or FRMAT (5762H).

The BACKUP path performs a sector-by-sector mirror-image copy of one diskette to another. It reads the source directory track, optionally honors the backup-counter protection scheme (see CNT1 / CXFLAG below) by decrementing the restricted-file counter on the source and de-allocating "count-exhausted" files before they are copied, writes the copy to the destination, and verifies the result. The routines RGRAN/WGRAN/VGRAN (at 517DH/519AH/51BBH) handle granule-level disk I/O; a granule in TRSDOS v1.3 is 3 sectors.

The FORMAT path (entry FOMAT, 5803H) issues the WD1793 RESTORE command to position the heads at track 0, builds a 256-byte track image in RAM using the TRKIMG/TBLBMP/EXPAND table-driven generator (5C1FH/5C7BH/5C8CH), writes that image to every track on the destination diskette (via TRKWRT at 5AB0H and VERFIT at 5AEEH for verification), and finally writes a bootstrap program to track 0 sector 1 and a dummy directory to track 17. The bootstrap code itself is the ENT routine (physically stored at 5853H but assembled to run at 4300H via a SETLOC BUFF1 directive); see the Cross-references section for how the two-cursor assembly works.

SYS7 does not handle any SVC (supervisor call) vectors directly — it is a transient utility overlay rather than a resident DOS component. It calls into SYS0 services (sector I/O at XREAD/XWRITE, drive select DSEL0, delay SDELAY, error reporting, ROM character-print PRINT at 021BH) and exits back to DOS READY by executing RET from BEGIN.

Memory Map

Range	Label	Contents
4E00H–4E7BH	FATAL / error handlers	Error-exit, abort, retry, and buffer-clear routines (FATAL, N12, RESTRY, ABRT, EXIT, CLRBUF). These are always at the start of every overlay so that a jump to 4E00H with a status byte in A produces a uniform DOS error message.
4E7CH–4EAAH	SDFLAG / workspace	Single-byte flags and word-sized workspace variables: drive numbers, side flags, flaw counts, compare flags, buffer pointer, memory top, date buffer, disk name buffer.
4EABH–4EDEH	READM / WRITM / VERFM / REST / FTRACK / SEC	Status message strings embedded in code space (“Reading”, “Writing”, “Verifying”, with track/sector placeholders filled in by OUTHEX).
4EE2H–516DH	ANALYZ / SRCMSG / DESMSG / ...	User-facing prompt messages: source disk, destination disk, data disk prompts, password prompts, invalid-password, N12M (“Cannot Backup”), ABMSG (“Operation ABORTED”), GEORGE (DEFE-encoded backup-count / restricted-files warnings), REFORM (re-format prompt), and the FORMATTING/TRACK display messages (FDSMSG, FDS, FDD).
516EH–51D7H	SPRINT / RGRAN / WGRAN / VGRAN	Display helpers and granule-level disk I/O primitives. SPRINT decodes DEFE-encoded strings. RGRAN/WGRAN/VGRAN wrap a 3-sector DJNZ loop around the sector primitives at FUNCTA/B/C.
51D8H–5237H	FUNCTA / FUNCTB / FUNCTC / GREAD / OUTHEX	Sector-level read/write/verify with status-message formatting; GREAD displays “Reading TT SS” / “Writing TT SS” / “Verifying TT SS” and invokes the SYS0 I/O. OUTHEX converts a byte to two ASCII decimal digits for the sector display.
5238H–527BH	BUMP / GBUMP / RBOOT	Buffer-pointer advance helpers; RBOOT reads the source boot sector and processes the CUSTomer-protection counter (decrements it, checks for zero).
52B4H–537BH	RDIR / WDIR / EXMGRN / DEALOC / RELEAS	Directory management: read directory into RAM, write directory back, examine each directory granule for count-protected files, de-allocate a file's granules, release a single segment descriptor.
537CH–5464H	RELEAS / CLRBIT / MEMCHK / MWRIT / FALOC / MREAD	Low-level allocation helpers: clear a bit in a FAT/GAT byte, check memory availability, write a range of granules out, find the next allocated granule, read a range of granules in.
5465H–548FH	FWAIT / LOOPY / LOOPX / LINOFF	“Flashing prompt” helpers that blink a message until the user hits a key.
5492H–5558H	CKSRC / CKDES / DGAT / CKSYS	Source-diskette, destination-diskette, and system-diskette prompt routines that flash the appropriate message and wait for the disk change.
5560H–5625H	BPREP / GETSRC / GETDES	Backup preparation loop; prompt for and validate source and destination drive numbers.
5626H–5713H	GETFOR / INPUT / GETPSF / GETPSB / GETNAM / GETDAT / CLRGAT / SETDAT	FORMAT-specific prompts: which drive to format, disk name, date, master passwords; clear the new GAT; set the “data diskette” flag.
5714H–5761H	DOTITL / COMON / BACKP	Clear screen, draw title banner, set up RAM buffers, BACKUP utility entry.
5762H–57A0H	FRMAT	FORMAT utility entry; prompt for drive and issue FOMAT.
5762H–57A0H (shared)	—	FORMAT/BACKUP common initialization.
57A1H	BEGIN	Overlay entry point. Called by SYS6 when the user invokes FORMAT or BACKUP.
57C3H–5802H	TRAP	Trap-door-code (password hash) calculation routine.
5803H–5852H	FOMAT	FORMAT inner-loop entry: RESTORE to track 0, drive-ready wait loop, CALL FORM to build the track image, CALL BOTWRI to write the boot track, then RET.
5853H–5952H	BOOT / ENT (relocated)	The 256-byte bootstrap program. Physically stored here, but the label ENT resolves to 4300H (via SETLOC BUFF1) so that JPs/CALLs within this block work when the code is copied to 4300H by the boot ROM. This code implements the load-file reader that pulls SYS0 off track 0 at power-on.
5953H–5963H	SYST / NOSYS (relocated)	Three-byte header followed by the tiny “NO SYSTEM” routine that is written to sector 2 of freshly formatted disks with no system, assembled to run at 4D00H (via SETLOC BUFF2).
5964H–5B54H	WRTDIR / VERMSG / FORMSG / STEPR / misc strings	Formatting-progress messages (“Writing System Information”, “Verifying Track nn Sector nn”, “Formatting Track nn Sector nn”), STEPR single-track step helper, and miscellaneous routines.
5A53H–5AADH	BOTWRI	Writes the bootstrap (from 5853H), NOSYS (from 5953H), GAT, and HIT to track 0 and track 17 sector 1 of the destination diskette.
5AB0H–5AEDH	TRKWRT	Issues a “write track” command to the WD1793 and streams the 4096-byte track image (from the BUFF area) through port F3H using INI instructions.
5AEEH–5B34H	VERFIT	After writing a track, read back every sector and verify; calls CALL to ASCII+PDATA to display “Verifying Track nn Sector nn”.
5B35H–5B54H	STEPR	Step the head one track inward and update the DOS track table.
5B55H–5B66H	ASCII / SUB / ADD	Convert a byte 0–99 into two ASCII decimal digits at (HL).
5B67H–5B6CH	PDATA	Display the string at (HL) via ROM PRINT, preserving DE.
5B6DH–5C1EH	WRTDIR / VERMSG / FORMSG / TRKNN / DDST / DDTAB / DDREP / DDTRK / DDSID / DDSEC / DDDATA / COPY / DDTRL / SECTAB / CSECTB	String constants and the track-building data block used by TRKIMG/EXPAND to compose a formatted track image in RAM.
5C1FH–5C8BH	TRKIMG / TBLBMP	Given a track number and side, build a full 256-byte track image in the BUFF area by expanding the DDST table.
5C8CH–5CBBH	EXPAND	Inner loop of TRKIMG that expands a single table entry (count byte + data or repeat pattern).
5CBDH–5D71H	FORM / FLAWX	Top-level FORMAT loop: fill a dummy directory buffer, iterate over every track on every side, call TRKIMG + TRKWRT + VERFIT, handle flawed-track reporting via the FLAW table.
5E00H–5EFFH	SPAR_	Scratch buffer (SECTOR bytes = 256).
5F00H–5FFFH	DUM1	Dummy directory sector buffer (256 bytes).
6000H–60FFH	SGAT	Source GAT sector buffer (256 bytes).
6100H–615FH	FGAT	Fresh GAT table with name and date (FLAW=96 bytes).
6160H–61FFH	FLAWD	Destination flaw table (160 bytes).
6200H–62FFH and beyond	BUFF	Main sector/track I/O buffer (256 bytes for sector I/O, extended to ~4KB for track-write operations).

Complete Variable List

All single-byte flags, word-sized pointers, and message buffers defined in the SYS7 workspace. Per the site-wide convention, these overlay-internal variables are not included in the RAM addresses JSON (they are ephemeral workspace for the duration of a FORMAT or BACKUP), but they are documented here for reference during analysis.

Address	Label	Description
4E7CH	SDFLAG	Single-disk flag (non-zero when source and destination are the same drive).
4E7DH	FDRIVE	Generic "current" drive number used by some shared code paths.
4E7EH	FDRIVS	Source drive number for the current BACKUP operation.
4E7FH	FDRIVD	Destination drive number for the current BACKUP or FORMAT operation.
4E80H	FLAWC	Flaw count (number of bad tracks detected on the destination during FORMAT).
4E81H	BSIDES	Source side number (0 or 1, for double-sided media).
4E82H	BSIDED	Destination side number.
4E83H	FLAG	General-purpose control flag.
4E84H	CLFN	Current logical file number (while walking the directory).
4E85H	CXFLAG	“Count flag” — set non-zero when the source boot's backup counter has reached zero; tells RDIR to de-allocate restricted files.
4E86H	CCFLAG	“Copy count” flag — set when at least one restricted file was actually de-allocated, so that GEORGE's “Protected Files NOT Backed Up” message is displayed.
4E87H	SINGLE	Single-density flag for the current operation.
4E88H–4E89H	PTRAP	Two-byte trap-door code (password hash) for the current file.
4E8AH–4E8BH	CSAVE	Two-byte saved HL (used by various subroutines as a scratch pointer save).
4E8CH–4E8DH	BUFPNT	Current sector buffer pointer (BUFF, BUFF+SECTOR, BUFF+2*SECTOR as the granule advances).
4E8EH–4E8FH	MEMTOP	Saved top-of-memory from DOS, restored at RET.
4E90H–4E97H	DATBUF	Eight-byte date buffer (MM/DD/YY).
4E98H–4EA0H	NAMEBF	Eight-byte disk-name buffer (shown in the directory header).
4EA2H–4EAAH	NAMBUF	Nine-byte scratch buffer for collecting user-entered disk name (one extra byte for terminator).
4EABH–4EB5H	READM	11-byte “Reading Track nn Sector nn” message template.
4EB6H–4EC0H	WRITM	11-byte “Writing Track nn Sector nn” message template.
4EC1H–4ECBH	VERFM	11-byte “Verifying Track nn Sector nn” message template.
4ECCH–4ED2H	REST	Rest-of-message trailer for the three templates above.
4ED3H–4EDDH	FTRACK	“Track nn” ASCII placeholder (overwritten each sector).
4EDEH–4EE1H	SEC	“Sec nn” ASCII placeholder.
4EE2H–4F16H	ANALYZ	“Analyzing Destination” message.
4EF7H–4F3BH	SRCMSG / DESMSG	“Insert SOURCE diskette” / “Insert DESTINATION diskette” messages.
4F3CH–4F75H	SYSMSG / BCOMP	“Insert SYSTEM diskette” / “Backup Complete” messages.
4F76H–4FA1H	TITLE1 / TITLE2	Screen banners for FORMAT and BACKUP.
4FA2H–4FF0H	FMSG / FDRV / DDATA	“Format which drive?”, drive-number prompt, and data-disk messages.
4FF1H–5030H	NAMMES / PASMES / SPASS	Name, password, and master-password prompts.
5031H–5078H	INVPAS / SDRV / DDRV	Invalid-password, source-drive, destination-drive prompts.
507AH–50B2H	N12M	“Cannot Backup a TRSDOS 1.1 diskette” fatal message (DEFB length + text).
50B3H–50DEH	ABMSG	“Operation ABORTED” message.
50DFH–511CH	GEORGE	Two DEFE-encoded messages: “Maximum Backup Count Exceeded” and “Protected Files NOT Backed Up” (the tilde ~ acts as terminator; each byte is XORed with 55H).
511DH–5144H	REFORM	“Do you wish to RE-FORMAT?” prompt.
5145H–516DH	FDSMSG / FDS / FDD	Source-drive / destination-drive format messages.
5875H	CNT1	Backup protection counter embedded in the bootstrap. FFH = unlimited backups; any other value limits the number of backups for files flagged with bit 5 of the directory entry.
593DH–593EH	TRKSAV	Two-byte save of current track/sector during boot-file reading.
593FH	EOFBYT	Sentinel/flag set when the boot-load file end-of-program record (02H) is encountered.
5940H–5946H	DSKERR	“ERROR” message embedded in the relocated ENT block.
5947H–5951H	S1SER / S1SIDE / TYPES / TRACKS	Serial number, side, type, and tracks fields written into the boot sector.
5953H–5955H	SEC3 / LEFT / NOSYS	Three-byte header (count byte + DEFB RIGHT + DEFW NOSYS) prefixed to the “NO SYSTEM” program.
5B6DH–5BB4H	WRTDIR / VERMSG / VERASC / FORMSG / FORASC	“Writing System Information”, “Verifying Track”, “Formatting Track” message templates with ASCII placeholder slots.
5BB5H–5C1EH	TRKNN / DDST / DDTAB / DDREP / DDTRK / DDSID / DDSEC / DDDATA / COPY / DDTRL / SECTAB / CSECTB	Track-building data block used by TRKIMG/EXPAND to compose the formatted-track image in RAM.
5CBCH	WORK	One-byte work location inside EXPAND (current sector number being expanded).
5D61H	FLAWX	Flaw-exception table pointer.

Major Routine List

Entry point address, label, and the source-file HEADER description for every named routine in SYS7. Addresses in the 4E00H–57FFH range and the 5853H–5D71H range were cross-verified against the binary; addresses in the 5800H–5852H FOMAT block match the source-derived walker output exactly.

Address	Label	Description / Purpose
4E00H	FATAL	Error handler entry. Called with error code in A. Prints the DOS error message and exits to DOS READY.
4E1DH	FATAL1	Inner entry to the error handler (skips the initial PUSH AF).
4E35H	N12	Abort with “Cannot Backup a TRSDOS 1.1 diskette” message.
4E41H	RESTRY	Reset the disk-retry counter in SYS0 workspace.
4E4AH	ABRT	Display “Operation ABORTED” and exit.
4E50H	EXIT	Clean exit: restore MEMTOP and return to DOS.
4E6EH	CLRBUF	Clear the sector I/O buffer area.
516EH	SPRINT	Decode a DEFE-encoded string (count byte + XOR-55H-scrambled chars) and display it.
517AH	RNEXT	Read the next granule (advances BUFPNT first, then falls through to RGRAN).
517DH	RGRAN	Read a granule (3 sectors) from disk. Entry: DE = starting track/sector, HL = buffer, C = drive.
519AH	WGRAN	Write a granule (3 sectors) to disk.
51BBH	VGRAN	Verify a granule (3 sectors) by reading back and comparing.
51D8H	FUNCTA	Read a sector with message display.
51E2H	FUNCTB	Write a sector with message display.
51ECH	FUNCTC	Verify a sector with message display.
522CH	OUTHEX	Convert register A (0–99) to two ASCII decimal digits at (HL).
5238H	BUMP	Advance BUFPNT by one sector (256 bytes) and bump the sector number.
5240H	GBUMP	Bump to the next granule (3 sectors), handling track wrap.
5257H	RBOOT	Read the source boot sector. Under CUSTomer assembly, decrement and check the backup-count protection counter.
52B4H	RDIR	Read the entire directory track into RAM.
52F2H	WDIR	Write the directory track back to diskette.
5312H	EXMGRN	Examine a directory granule for files flagged as count-restricted.
5351H	DEALOC	De-allocate a restricted file that has exhausted its backup count.
537CH	RELEAS	Release a single segment descriptor (SD) from the GAT.
53ADH	CLRBIT	Clear bit A of register B (helper for FAT manipulation).
53BAH	MEMCHK	Test whether enough memory is available for a RAM-buffered backup.
53D3H	MWRIT	Write a range of granules from a RAM buffer to diskette.
53FAH	FALOC	Find the next allocated granule on diskette.
5438H	MREAD	Read a range of granules from diskette into a RAM buffer.
5465H	FWAIT	Flash a message and wait for a keypress.
5492H	CKSRC	Flash “Insert SOURCE diskette and press ENTER” and wait.
54A5H	CKDES	Flash “Insert DESTINATION diskette and press ENTER” and wait.
54B9H	DGAT	Destination GAT validation.
5509H	CKSYS	Flash “Insert SYSTEM diskette” and wait.
5560H	BPREP	Backup-preparation dispatcher (entered from BACKP).
55CCH	GETSRC	Prompt for and validate the source drive number.
55F4H	GETDES	Prompt for and validate the destination drive number.
5626H	GETFOR	Prompt for the drive to FORMAT.
5645H	INPUT	Display a prompt and collect one line of user input.
5652H	GETPSF	Prompt for the FORMAT master password.
5657H	GETPSB	Prompt for the BACKUP master password.
5666H	GETNAM	Prompt for and collect the new disk name.
568CH	GETDAT	Prompt for and collect the date.
5693H	CLRGAT	Clear the new GAT and initialize it with the disk name and date.
56ABH	SETDAT	Set the “data diskette” flag in the new GAT.
56B1H	CHKFOR	Analyze the destination diskette to see whether it already has data (and prompt for RE-FORMAT confirmation if so).
5714H	DOTITL	Clear screen and display the FORMAT or BACKUP title banner.
5728H	COMON	Common initialization shared by both FORMAT and BACKUP paths.
5739H	BACKP	BACKUP utility entry. Called by BEGIN when the command is BACKUP.
5762H	FRMAT	FORMAT utility entry. Called by BEGIN when the command is FORMAT.
57A1H	BEGIN	Overlay entry point. Parses the command line, dispatches to BACKP or FRMAT.
57C3H	TRAP	Compute a trap-door code (password hash) from an input string.
5803H	FOMAT	FORMAT engine: RESTORE head, drive-ready wait, CALL FORM to build the track image, CALL BOTWRI, CALL verify.
5853H	BOOT	Physical address of the bootstrap program (emission cursor). Label ENT (which resolves to 4300H) marks the same bytes' intended run-time address.
5A53H	BOTWRI	Write the bootstrap, NOSYS, GAT, and directory sectors to the destination disk.
5AB0H	TRKWRT	Issue “write track” to the WD1793 and stream the track image out.
5AEEH	VERFIT	Verify every sector on the just-written track by reading it back.
5B35H	STEPR	Step the head one track inward; update the DOS track table entry.
5B55H	ASCII	Convert an 8-bit value (0–99) to two ASCII digits at (HL).
5B67H	PDATA	Display the string at (HL) via ROM PRINT, preserving DE.
5C1FH	TRKIMG	Build a full 256-byte formatted track image in the BUFF area from the DDST template table.
5C7BH	TBLBMP	Helper used by TRKIMG to fetch table pointers from the IY-indexed table descriptor.
5C8CH	EXPAND	Inner loop that expands one table entry into the track image (count + pattern repetition).
5CBDH	FORM	Top-level FORMAT routine: set up the track-building tables, iterate over every track, call TRKIMG + TRKWRT + VERFIT for each.

Cross-references and Analysis Notes

During the source-to-binary cross-check for SYS7, the following observations were recorded. They are preserved here so that future sessions on this overlay do not repeat the same investigation.

• Two-cursor SETLOC assembly. The BOOT: EQU $ / SETLOC BUFF1 / RESLOC pattern at the head of the bootstrap block causes two distinct address contexts to apply to the same bytes. The load-file emission cursor continues linearly from the end of FOMAT, so the bootstrap bytes live at 5853H+ in the overlay image; but the $ location counter is redirected to BUFF1 = 4300H so that labels inside the block (ENT, TRYAGN, BOTLOP, GETBYT, etc.) resolve to the addresses the code will occupy at run-time. Any JP/CALL to those labels inside the block therefore encodes the 4300H target, which is correct because the DOS loader copies the block to 4300H before transferring control.
• DEFE pseudo-op in GEORGE messages. The two DEFE strings at 50DFH (“Maximum Backup Count Exceeded~”) and at 50FDH (“Protected Files NOT Backed Up~”) each emit a leading length byte followed by the string chars XORed with 55H. Each string occupies len(string) + 1 bytes. SPRINT at 516EH reads the count byte into B, INCs HL, then XORs each character on its way to the ROM print routine. The trailing ~ character is part of the string itself and serves as the user-facing end-of-message marker after decoding (~ XOR 55H = 0DH = carriage return).
• Copy-protection counter (CNT1). At 5875H inside the bootstrap is a one-byte counter initialized to FFH (unlimited). A customer-site tool could set this to a small integer; RBOOT decrements it on each successful BACKUP read. When the counter reaches 0, the CXFLAG is set, and RDIR then calls DEALOC on every file flagged with bit 5 in its first directory byte — effectively removing those files from the backup. CCFLAG is set if any such file was actually removed, triggering the “Protected Files NOT Backed Up” warning.

4E00H - FATAL - This is the ERROR, EXIT, and FATAL ERROR Routine. This is not the Overlay entry point (which is 57A1H).

4E35H - N12 - ABORT with CAN'T BACK UP DISKETTE Message

4E41H - RESTRY - Reset the Retry Counter in DOS

4E4AH - ABRT - ABORT routine - Jumped to if there was an error along the way

4E6EH - CLRBUF - Clear RAM from 5E00H to 5EFFH and return

4E7CH - SDFLAG - MESSAGE and BYTE STORAGE AREA

Message Storage Areas

NOTE: The original source does not have 5138H-5144H

Additional Message Storage

516EH - SPRINT - Decode and Display a Coded String

517AH - RNEXT - Read a Gran. A Gran in TRSDOS v1.3 is 3 Sectors. D=Track Number, E=Sector Number, HL=Buffer for Storage

519AH - WGRAN - Write a Gran. On entry, HL points to the Data Buffer to Write to Diskette

51BBH - VGRAN - Verify a Gran

51D8H - FUNCTA - Read a Sector and Display a Message

51E2H - FUNCTB - Write a Sector and Display a Message

51ECH - FUNCTC - Verify a Sector and Display a Message

520BH - GREAD1 - Display the appropriate Reading/Writing/Verifying Track xx Sector yy Message. On Entry, IY is pointing to a message of Reading, Writing, or Verifying, D holds the track number, and E holds the sector number

522CH - OUTHEX - Convert the Value in Register A into a Two Digit Decimal, stored in (HL)

5238H - BUMP - Move to the Next Sector Buffer for a Given Gran. Since a Gran is 3 Sectors, processing a gran requires moving between 3 memory buffers. On Entry, D holds the Track, E holds the Sector Number, and HL points to the associated Data Buffer

5240H - GBUMP - Move to the next Gran Buffer in a Given Track

5257H - RBOOT - Copy of the BOOT Sector and Check for Permitted Backup

52A9H - RBOOT1 - Continuation of BACKUP Routine. Jumped here if no more permitted backups can be made

52B4H - RDIR - Read the Directory Track into RAM

52F2H - WDIR - Write the Directory Track

5312H - EXMGRN - Examine a Directory Gran for Files which are limited backup

EXMGRN Routine Completion

5351H - DEALOC - De-Allocate a File which was Protected. On Entry, HL points to the director record to deallocate.

5364H - DEALC2 - Clear the Directory Entry following a De-Allocation.

537CH - RELEAS - De-Allocate All Grans in a Given Extent. On Entry, DE is the segment descriptor.

53ADH - CLRBIT - Reset Bit (A) of Register B. On Entry, A contains the bit to reset and B contains the byte to reset.

53D3H - MWRIT - Write the Grans from the RAM BUFFER to the DISKETTE.

53FAH - FALOC - Find the Next Allocated Gran on Diskette.

5409H - FALOC2 - Determine Which Track was Allocated.

5438H - MREAD - Read granules from the source diskette. On exit, the C FLAG will be set if the buffer is full.

5454H - MREAD2 - Read Granules from RAM to Diskette.

545EH - MREAD3 - Mark the END OF DATA in the BUFFER.

5465H - FWAIT - Flashing Prompt Routine.

5488H - LINOFF - SUBROUTINE in the Flashing Prompt Routine to clear a line.

5492H - CKSRC - Prompt for the SOURCE DISK (if necessary).

54A5H - CKDES - Prompt User for the Destination Disk.

54B9H - DGAT - Check Destination Diskette.

5509H - CKSYS - Prompt the User for the SYSTEM DISK (if necessary).

5518H - DOLLAR - Copy the Source Diskette to the Destination Diskette.

5560H - BPREP - Start of the backup routine ... first Check the Source Diskette.

55B3H - BPREP1 - Continuation of the BACKUP routine; Jumped here if the user supplied the correct master password.

55CCH - GETSRC - Get and Validate the Source Drive Number.

55F4H - GETDES - Get and Validate the Destination Drive Number.

5626H - GETFOR - Get the Number of the Drive for the FORMAT.

5645H - INPUT - Prompt the user with a message and fetch B characters from the user. On entry, HL points to the text to display and B holds the maximum character count to accept.

5652H - GETPSF - Prepare to display the prompt for the MASTER PASSWORD.

5657H - GETPSB - Prompt the user for the master password for the source diskette.

5666H - GETNAM - Get the NAME for the DISKETTE to FORMAT and put it in 4E98H-4EA0H.

568CH - GETDAT - Generate the Date in ASCII from the SYSTEM CALENDAR.

5693H - CLRGAT - Generate a Formatted Diskette's GAT TABLE (meaning identify the BOOT and DIRECTORY tracks aas allocated).

56ABH - SETDAT - Set the flag to prompt for the SYSTEM DISKETTE once the current operation is completed.

56B1H - CHKFOR - Analyze the Destination Diskette for a Prior Format.

56E9H - CHKFO2 - Continuation of the above ANALYZE A DESTINATION DISKETTE routine; jumnped here if there is an active file present. On Exit A is ZERO if we are not reformatting; and anything else if we are.

5714H - DOTITL - Clear the Screen and Display a Program Name. On Entry, HL points to the middle part of the applicable message.

5728H - COMON - Common Routine for both BACKUP and FORMAT - Set up the RAM BUFFERS.

5739H - BACKP - "BACKUP" Utility.

5762H - FRMAT - "FORMAT" Utility.

57A1H - BEGIN - DOS Entry to the FORMAT and BACKUP Utilities.

57C3H - TRAP - Encode a Password.

57D3H - NOSPC - Password Encode. Encode the password stored in the memory location pointed to by Register Pair DE; results in Register Pair HL.

5803H - FOMAT - Format a Diskette.

5832H - L2OOP - Continuation of FORMAT routine above; jumped here once we hit track 0.

4300H - ENT - EXACT COPY OF BOOT/SYS ... This is what gets dumped onto a disk. The JUMP values do not match the instruction addresses because it will be Relocated

4322H - CNT1 - Data Byte. Number of Backups Permitted.

4323H - BOTLO1 - Read a Data Block from Diskette into a Memory Buffer Pointed To By HL. If we are here, the byte we read from disk was a DATA BLOCK designator.

5888H - GETADD - Get an address from diskette. Basically, this just reads 2 bytes into Register Pair HL; LSB into L and MSB into H.

5891H - GETBYT - Read a Byte from Diskette

58B7H - GETOK - Jumped to by 434FH if we weren't originally at the sector we wanted, but we are now.

58D2H - BOTRED - Read a Sector from Diskette

590AH - BOTINT - This routine was set as the INTERRUPT VECTOR at 438AH. This routine exits with Register A holding the FLOPPY DISK CONTROLLER status.

5918H - XSEEK - Routine to position the read head based on the contents of HL (H=Track, L=Sector)

5933H - DELY - Routine delay Of 2 Lengths (Depending on Entry). Used primarily as a short delay between OUTputting to the FDC and INputting from the FDC.

593DH - TRKSAV - MESSAGE and BYTE STORAGE AREA.

5957H - NOSYS - Display NOT A SYSTEM DISK and Freeze the System.

5964H - SYSTMG - MESSAGE and BYTE STORAGE AREA.

5A53H - BOTWRI - Write the Bootstrap, System, and Directory to Diskette.

5AB0H - TRKWRT - Write a Track of Data.

5AEEH - VERFIT - Verify One Track.

5B35H - STEPR - Position the Diskette Head to the Track held in Register C.

5B55H - ASCII - Convert Register A into a Two Digit Decimal to be stored at (HL).

5B5FH - ADD - Continuation of the routine to convert Register A into a Two Digit Decimal to be stored at (HL), jumped here once we have a remainder.

5B67H - PDATA - Display a Message.

5B6DH - WRTDIR - MESSAGE and BYTE STORAGE.

5BB5H - TRKNN - This is the phrase address list.

5C0AH - SECTAB - MESSAGE and BYTE STORAGE - Sector Number Table.

5C1FH - TRKIMG - Generate the Track Image Area into the Buffer. On Entry, C contains the Track Number.

5C6BH - TRKIM4 - Continuation of the Generate the Track Image Area; jumped here when we have reached the end of the SECTOR NUMBER TABLE.

5C7BH - TBLBMP - Retrieve the Table Addresses.

5C8CH - EXPAND - Use the Track Building Table to fill up the table pointed to by DE.

5CA2H - NOCOPY - Continuation of the routine to Use the Track Building Table to fill up the table pointed to by DE; jumped here if we did not hit the copyright message.

5CBDH - FORM - FORMAT and VERIFY a DISK.

5D60H - MESSAGE and BYTE STORAGE - Final Data Areas.

Entry Point and Initialization