The Programmer's Guide to TRSDOS Version 6 - Tim Mann's Home ...

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Hard drives generally cannot be backed up in a mirror-image manner and the BACKUP utility will prohibit it by automatically entering the RECONSTRUCT mode. 5.2.4 DOS VERSION - This field contains the operating system version used in formatting the disk. Disks formatted under DOS 6.0 will have a value of X'60' contained in this byte. It is used to determine whether or not the disk contains all of the parameters needed for DOS 6.0 operation. 5.2.5 CYLINDER EXCESS - This byte contains the number of logical cylinders in excess of 35. It is used to minimize the time required to compute the maximum cylinder formatted on the diskette and to update the Drive Control Table. It is designed to be excess 35 so as to provide complete compatibility with previous systems that restricted the floppies to 35 tracks and did not maintain the byte. This field is read to update the Drive Control Table during the process of logging the disk by the @CKDRV SuperVisor Call process. 5.2.6 DISK CONFIGURATION - This byte contains data specific to the formatting of the diskette. It is fielded as follows: Bit 7 Set to "1" indicates the disk is a DATA disk; thus all but two directory slots are available for data files. Set to a 0 indicates that the disk is a SYSTEM disk which reserves 14 additional directory slots for system files providing a maximum of 240 directory entries for data files. Bit 6 Set to "1" implies double density formatting. Set to 0 implies single density formatting. Bit 5 Set to "1" indicates two-sided floppy media. Set to 0 indicates single-sided floppy media. Bit 4 This is reserved for internal system use. Bit 3 This is reserved for internal system use. Bits 2-0 Contain one less than the number of granules per track that were used in the formatting process. 5.2.7 DISK PACK PASSWORD - This field contains the 16-bit hash code of the disk master password. Its storage is in standard low-order high-order format. The password itself must be composed of the characters with the first character alphabetic. The 16-bit hash code can be obtained from the DOS for any given password. This is done by placing the password string into an 8-character buffer left-justified and padded with spaces, and then invoking a system overlay. The following code illustrates this operation. HASHMPW LD DE,PSWDPTR ;Point to the 8-char buffer LD A,0E4H ;Specify password hash function RST 40 ;Issue the RST instruction The 16-bit password hash code will be returned in register pair HL. Registers AF, B, DE, and HL are altered. The operating system will not return to the address following the RST 40 instruction when the SVC function code is an internal system request code (i.e. has bit-7 set) but will return to the previous caller. Thus, it is necessary to CALL this routine. 5-4
5.2.8 PACK NAME - This field contains the diskette pack name. This is the same name displayed at boot up if the diskette is a system diskette used for the boot operation [specifically, the boot name is obtained from the System Information Sector but is managed coincidentally by FORMAT and ATTRIB. It is also the name displayed during a FREE or DIR or obtained by the @DODIR SuperVisor Call. The name is assigned during the formatting operation or reassigned during an ATTRIB renaming operation. 5.2.9 PACK DATE - This field contains the date that the disk was formatted or the date that it was used as the destination in a mirror-image backup operation. If the diskette is used during a BOOT, this date will be displayed adjacent to the pack name [actually, the boot date is obtained from the System Information Sector but is managed coincidentally by BACKUP]. 5.2.10 RESERVED FIELD - This field is reserved for future use under DOS version 6. It formerly contained the AUTO command buffer under earlier versions of the DOS; however, since Version 6 supports 79character command lines, the System Information Sector now holds the AUTO command buffer for use during a BOOT operation. 5.2.11 MEDIA DATA BLOCK - Effective with LDOS 6.2.0, this field contains a header sub-field and a sub-field replicating the last seven bytes of the drive control table in use and associated with the media when the media was formatted. Bytes 0-3 contains an X'03' followed by the string, "LSI". Bytes 4-10 replicates the last seven bytes of the DCT during format. ============================================================ | 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F | | _______________________________________________ | | 00 | | 00 | | 01 | | 01 | | 02 | ALLOCATION TABLE | 02 | | 03 | | 03 | | 04 | | 04 | | 05 |_______________________________________________| 05 | | 06 | | 06 | | 07 | | 07 | | 08 | FLOPPY LOCKOUT TABLE | 08 | | 09 | HARD DRIVE ALLOCATION TABLE | 09 | | 0A | | 0A | | 0B |_______________________________________________| 0B | | 0C |_E_X_T_E_N_D_E_D___A_L_L_O_C____|_#|_+|_*|_MPW_| 0C | | 0D |___P_A_C_K___N_A_M_E___|___P_A_C_K___D_A_T_E___| 0D | | 0E | R E S E R V E D | 0E | | 0F |_______________________________________________| 0F | | | | 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F | | | | Note:"#"= DOS Version;"+"= Cyl Excess;"*"= Configuration | | | ============================================================ Figure 5-3: Granule Allocation Table Illustrated 5-5
Page 1 and 2: MISOSYS, INC. The Programmer's Guid
Page 3 and 4: 1. Introduction Many thousands of u
Page 5 and 6: language (i.e. BASIC, C, PASCAL, ..
Page 7 and 8: NAME START END DESCRIPTION LOWCORE
Page 9 and 10: ackup utility provides exceptional
Page 11 and 12: 3. Device Input/Output Interfacing
Page 13 and 14: 3.2.2 VECTOR Field - This field in
Page 15 and 16: FILTER *PR USING *S0 the operating
Page 17 and 18: ===================================
Page 19 and 20: ===================================
Page 21 and 22: ENTRY JR BEGIN ;Branch around linka
Page 23 and 24: DATA1 EQU $-DATA$ DB 0 ;Data storag
Page 25 and 26: Offset Contents +0 Contains the las
Page 27 and 28: image of the serial port UART statu
Page 29 and 30: called TRACKs. Each track is then d
Page 31 and 32: The DCT contains the information re
Page 33 and 34: accessed a single-sided diskette, t
Page 35 and 36: containing the disk's directory. Th
Page 37 and 38: Command Purpose RESTORE Recalibrate
Page 39 and 40: available from Logical Systems, Inc
Page 41 and 42: exceeds this capacity, then it must
Page 43 and 44: is two physical cylinders. Although
Page 45 and 46: 5. The DOS Directory Structure 5.1
Page 47: ===================================
Page 51 and 52: The position of a file's hash code
Page 53 and 54: 5.4 THE DIRECTORY RECORD STRUCTURE
Page 55 and 56: Bit 3 Specifies the visibility; if
Page 57 and 58: the first granule in use is the sec
Page 59 and 60: travels the turnpike. In this manne
Page 61 and 62: The @FSPEC SVC will transfer the fi
Page 63 and 64: A high level language permits you t
Page 65 and 66: does exist, @RENAME should return e
Page 67 and 68: Next, it would be very useful if th
Page 69 and 70: LD HL,FCBX+9 ;Point to the LRL fiel
Page 71 and 72: operating system for such a purpose
Page 73 and 74: position where the last character i
Page 75 and 76: ecord. If a file has more than four
Page 77 and 78: DE Contains a pointer to the File C
Page 79 and 80: @RENAM SVC-56 Rename a file on disk
Page 81 and 82: @FNAME SVC-80 Obtain filespec given
Page 83 and 84: @WRSEC SVC-53 Write a disk sector @
Page 85 and 86: 7.6 SUPERVISOR CALL DETAILS 7.6.1 @
Page 87 and 88: Note: @EXIT in SYS1 automatically r
Page 89 and 90: 7.6.10 @CLOSE SVC-60 This SVC will
Page 91 and 92: 7.6.18 @DCSTAT SVC-40 This SVC pass
Page 93 and 94: Directory to Buffer Entry: B 1; Fun
Page 95 and 96: 7.6.31 @FLAGS$ SVC-101 This SVC wil
Page 97 and 98: NFLAG$ This "network" flag is used
Page 99 and 100:
7.6.32 @FNAME SVC-80 This SVC will
Page 101 and 102:
7.6.40 @HEX8 SVC-98 This SVC will c
Page 103 and 104:
7.6.48 @KLTSK SVC-32 This SVC will
Page 105 and 106:
7.6.57 @OPEN SVC-59 This SVC will o
Page 107 and 108:
Registers Affected: AF, BC. Entry:
Page 109 and 110:
0-14 FILENAME/EXT:D - left justifie
Page 111 and 112:
7.6.71 @REMOV SVC-57 This SVC will
Page 113 and 114:
Entry: DE A pointer to the FCB cont
Page 115 and 116:
Exit: A Error return code, if any.
Page 117 and 118:
CURSOR CHARACTER Registers Affected
Page 119 and 120:
Exit: A Will contain the error code
Page 121 and 122:
esident routine into its execution
Page 123 and 124:
CKPAWS LD A,@FLAGS$ ;Get Flags poin
Page 125 and 126:
===================================
Page 127 and 128:
The TYPE=0A indicates that it is th
Page 129 and 130:
Error 08: Device not available A re
Page 131 and 132:
Error 28: End of file encountered T
Page 133 and 134:
8.5 HEADER PROTOCOL OF MEMORY MODUL
Page 135 and 136:
This is obviously an extremely usel
Page 137 and 138:
LD (IX+2),15 JR TASKA By firmly und
Page 139 and 140:
8.7.3 Details of Low Memory Page 2
Page 141 and 142:
actual bank switching. As previousl
Page 143 and 144:
set. Thus, the Z-flag will be indic
Page 145 and 146:
8.10 SYSTEM DISK BOOT TRACK The ope
Page 147 and 148:
14 DEBUG 72 PURGE 1B VERIFY 71 DUMP
Page 149 and 150:
8.13 USING @PARAM The @PARAM SuperV
Page 151 and 152:
DW LPARM+1 DB 'FEED ' ;Line feed pa
Page 153 and 154:
;*=*=* PPARM LD BC,0 ;Zero because
Page 155 and 156:
8.14 TRAP Filter Illustrated ;TRAP/
Page 157 and 158:
8.15 SLASH0 Filter Illustrated ;SLA
Page 159 and 160:
8.16 DMP-500 BOLDFACE Filter Illust
Page 161 and 162:
NOMEM$ DB 'High memory is not avail
Page 163 and 164:
@ @ABORT..........7-2, 7-4, 7-8, 7-
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