LoadDskF & SaveDskF

LOADDSKF & SAVEDSKF User's Guide (c) Copyright International Business Machines Corporation 1993. All rights Reserved. 01/27/93 LOADDSKF & SAVEDSKF ___________________ INTRODUCTION ____________ SaveDskF.exe and LoadDskF.exe are a pair of utilities to save a diskette to a file and vice-versa. These programs are not intended to save fixed disk images. They have these characteristics: ¨ Run under OS/2 and DOS 3.3 or later. ¨ Empty sectors above the highest occupied sector are not included in the file. ¨ The data may be compressed. ¨ Diskettes may be formatted as they are written. ¨ Standard diskette formats are supported. ¨ Conversion to a larger diskette image is possible. ¨ Label text may be included in the file that is displayed by LoadDskF before the diskette is written. ¨ The progress of the data transfer is visible on the screen. ¨ Built-in Checksum function. ¨ Handles "image" files generated by other programs. Efficient portability of complete diskette images is pro- vided for transmission via data networks. Boot, file allo- cation table, directory and data sectors are included. Both programs provide a short help facility when some types of syntax errors are detected. Just type the program name to get help. LOADDSKF & SAVEDSKF 1 LOADDSKF ________ The calling syntax is: LoadDskF [D:][path]filename.dsk d:[/F][/C][/Y][/Q] The diskette image contained in the file is written to the specified target drive d:. The target diskette must have the same format as the original diskette. If the format is incorrect, an informational message indicates the required format. A warning message appears before the data transfer begins so that syntax errors do not result in a corrupted diskette. It is necessary to press the "y" key in order to continue the process. A return code of 31 (decimal) is issued if the response is not "y". Alternatively, /Y will bypass the need to press the "Y" key. When both /Y and /Q are invoked, the warning message is omitted. In the event of a checksum error, both the expected and cal- culated values are displayed. IMAGE FILES ___________ Loaddskf supports input files that represent a pure binary image of the disk that has been generated by SaveDskf with the /D and /A options or other programs, such as DSKIMAGE and DISKIMGE. Image is defined as the uncompressed disk data without header or trailer. The file must be the exact size of a standard diskette. Diskettes supported are 1.44M, 1.2M, 720K and 360K. FORMATTING __________ When /F is specified, each track is formatted before it is written. When all of the data has been written, LoadDskF continues to format the remainder of the tracks. LOADDSKF & SAVEDSKF 2 CONVERTING A DISKETTE _____________________ When /C is specified, the diskette image can be written on a diskette of a different format than the original diskette provided that it is at least as large as the original. The resultant diskette's capacity will then appear to have the original diskette's capacity. After executing LoadDskF /C, it is recommended that the files be transferred to another diskette using the DOS copy command. The diskette with the truncated capacity can then be reformatted. When you use the /C option together with the /F option, your diskette will be formatted to the highest density supported on the drive (not exactly true, but it will be most of the time). There is no means for specifying lower capacity me- dia. The image written to diskette will be logically the same as the source. There are some subtle differences, how- ever. Let's assume that we have a 1.2Mb image that we want to put onto a 1.44Mb diskette. There are 18 sectors per track on a 1.44Mb diskette. There are only 15 on a 1.2Mb diskette. In this case we would only write 15 of the 18. The boot record would tell us that there were only 15 sectors per track. This looks to DOS just as if it were a real 1.2Mb diskette. Physically, there are actually 3 sectors on each track that are not used. DOS is told they don't exist and it never looks for them. When you tell LoadDskF the /F option, it will format the output diskette to the same density as the input diskette image (providing, of course, that the diskette drive sup- ports that kind of image). If you ALSO use the /C option, your diskette will be format- ted to the highest density that the drive supports. If we assume we have a 2.88Mb diskette drive and a 1.2Mb or 1.44Mb diskette image, the diskette will be formatted to 2.88Mb. The image written to diskette will be either 1.44Mb or 1.2Mb. It will PHYSICALLY be formatted as 2.88Mb, but will LOGICALLY be a 1.44Mb or 1.2Mb diskette. If you first wrote the 1.44Mb image to a diskette and then used ONLY the /C op- tion and wrote a 1.2Mb image to the same diskette, it would work. If you now try to write a 1.44Mb image to the same diskette with only the /C option, it would fail. This is be- cause DOS thinks that you have a 1.2Mb diskette in the drive and a 1.44Mb diskette won't fit. In this case, you MUST use both the /C option and the /F option. It is important to understand that this is not an all encom- passing conversion from 3.5 to 5.25 inch media. In some in- stances, 3.5 inch media is provided for PS/2 systems and 5.25 inch media for PC systems. Therefore code that supports hardware may be different for each media type. LOADDSKF & SAVEDSKF 3 In those cases where the media type is unimportant, a file packager such as SaveRam or PKZIP is strongly recommended over SaveDskF so that those who receive the packed file need not have a particular type of diskette drive. PROGRESS INDICATION ___________________ As the data is written to the diskette, the percentage of the data which has been written is displayed on the screen. If the diskette is being formatted as it is written, the percentage is based on the diskette capacity. DOS COMPATIBILITY MODE ______________________ There is sometimes a problem when operating in the DOS com- patibility mode where DOS does not recognize the newly gen- erated diskette. When this happens, the diskette appears to have incorrect system information and it is necessary to partially remove it and re-insert it in the drive. UP/DOWN LOADING _______________ When transferring diskette image files between the PC and a host system, it is necessary to treat them as binary files, i.e. no translation of data must occur. If the file data has been translated, LoadDskF will usually give an error message indicating that the file is not compatible with LoadDskF. It is also necessary to download any executable file includ- ing LoadDskF.exe and SaveDskF.exe as binary files without translation. When translation occurs, the results are un- predictable and usually hang the machine requiring a power off/on sequence to get back into operation. LoadDskF will ignore any data at the end of a file that is shorter than a complete sector. This provides some forgiveness for the common error of uploading to a fixed re- cord length file on a host system which results in a mean- ingless string of data at the end of the file which is usually not longer than 80 bytes. LOADDSKF & SAVEDSKF 4 SAVEDSKF ________ The calling syntax is: SaveDskF d: [D:][path]filename.dsk [/D][/A][/N][/M][/K] Since the diskette that the file will be copied to by LoadDskF must be the identical format as the original, it may be helpful to give the file a name that is indicative of the required format, or include the diskette type in the commentary message (/K or /M flag). An extension of .DSK is recommended to indicate a diskette image file. The complete image of the diskette in drive d: is written to the specified file. A file header as described below and all diskette sectors are written up to and including the highest occupied data sector. Whether or not a data sector is in use is determined from the file allocation table. An informational message is displayed if some of the sectors written do not actually contain data. This means that there are some gaps in the data portion of the diskette. An ap- propriate response is to run a disk defragmentation program against the source diskette. Copy protected diskettes having non-standard sector numbers cannot be saved by SaveDskF. Only standard DOS formats are supported. As the data is written to the file, the percentage of the data which has been written is displayed on the screen. PURE DISKETTE IMAGE ___________________ The /D option omits the file header and inhibits compression of the diskette data. The resulting file is intended for use with diskette copying software and is not compatible with LoadDskF.exe unless the /A option is also used. When /D is specified, /K and /M will generate an error message. SAVE ENTIRE DISK ________________ The /A option saves the whole diskette regardless of the data stored on it. LOADDSKF & SAVEDSKF 5 DATA COMPRESSION ________________ The /N option inhibits data compression. This is useful when the compression algorithm fails and produces data that is larger than the uncompressed data. When this happens, SaveDskF displays an informational message recommending that you rerun the program with /N specified. COMMENTARY MESSAGE __________________ The /M option tells SaveDskF to get text from the specified file to be included as a comment in the diskette image file which LoadDskF will display before unloading the diskette data. It may contain information on any aspect of the diskette usage or the way it is to be unloaded. This pro- vides a means of ensuring that the recipient of the diskette will be aware of important information. The /K option allows you to type in a brief commentary mes- sage on the command line. The text must follow immediately and be enclosed in either single or double quotes. The en- tire command length is limited to 128 bytes. When enclosed in single quotes, double quotes may be used in the text and vice versa. If a message file has been specified with /M, the /K text is added to its contents. The total length of the message may be up to 4096 bytes. Examples of these flags are: SaveDskF a: test.dsk /k"This is a 1.44Mb diskette" OR SaveDskF a: test.dsk /m test.msg OR SaveDskF a: test.dsk /mtest.msg Where test.msg might contain: +--------------------------+ + This file could contain + + the text that you would + + want printed on the label+ + of the diskette. + +--------------------------+ LOADDSKF & SAVEDSKF 6