.ps 60,58 .lm 0 .rm 60 .title Amdohl-Vax Ascii Tape Utility .nofill .skip 22 .fill .center Amdohl-Vax Ascii Tape Utility (AVATU) .center Mostek Corp. .center 1215 West Crosby Road .center Carrolton, Texas 75006 .center Eddie Lui .center 12-Mar-81 .page .center PREFACE .center ------- .skip 2 .paragraph The purpose of the Amdohl-Vax Ascii Tape Utility is: .list .le;Allow a Vax system to read any IBM magtape which is written only with the Ebcdic-Ascii character set (ie. Ebcdic characters which have Ascii equivalents) and copy the magtape's contents into a disk file. .le;Allow a Vax system to write any Ascii only disk file onto a magtape in the appropiate format (Ebcdic) and content (labels,etc.) so that an IBM system can read the magtape. The magtape produced on the Vax system should not require any extra consideration than one which is created on an IBM system when it is read on an IBM system. .le;Provide a general tape utility to read and write any IBM (Ascii only) magtape on a Vax system. This is accomplished by simulating the algorithms the IBM system use to read and write magtapes. .le;Provide a resonable bulk throughput when reading and writing magtapes. .end list .page .subtitle Before running the utility .paragraph Before running the utility, the magtape of interest must be mounted on the a magtape drive as a foreign tape by using the MOUNT command. .literal $ MOUNT/FOREIGN/DENSITY=1600 MTA1: ANY__NAME note: MTA1 should be replaced with the appropiate magtape drive name in use. The density switch is required since most of the IBM tape drives are 1600 bpi only. ANY__NAME can be any name, the operating system uses the name to make sure no other tape mounted has the same name. .end literal .paragraph After the magtape is successfully mounted, the utility is invoked by entering AVATU as the command. .literal $ AVATU .end literal If the utility is successfully invoked, it will prompt the user for further input. AVATU's prompts follow the following conventions: .list .le;Along with each prompt, a list of acceptable inputs is clearly stated (if such a finite list exists). The list will indicate the acceptable inputs and what each input means. .le;For each prompt which has a default (ie., if the user just hit the for input), the default condition is enclosed in square brackets within the prompt. If the default is desired, then the user can enter an empty line as input. .end list .paragraph AVATU will prompt the user several times before it actually starts to read/write the magtape. The inputs to the prompts will allow the utility to finalize the run-time parameters. The following sections will describe each prompt and its acceptable inputs. Listed below is an abreviated summary of the prompts: .literal Reading a magtape: .end literal .list .le;ENTER TRANSFER MODE: (READ) .le;ENTER MAGTAPE UNIT NUMBER: .le;ENTER ESTIMATED FILE SIZE IN BLOCKS: .le;ENTER EXTENSION FILE SIZE IN BLOCKS: .le;ENTER VAX OUTPUT FILE NAME: .end list .literal Writing a magtape: .end literal .list .le;ENTER TRANSFER MODE: (WRITE) .le;ENTER MAGTAPE UNIT NUMBER: .le;CREATE VOLUME LABEL?: .le;ENTER VOLUME SERIAL NUMBER: (this prompt only if YES to previous prompt) .le;ENTER DATASET ID: .le;ENTER MAGTAPE BLOCK SIZE: .le;ENTER VAX INPUT FILE NAME: .end list .page .subtitle Transfer mode .paragraph The first prompt upon a successful invoke of the AVATU utility is the transfer mode prompt. The transfer mode prompt establishes to the utility whether the user is reading or writing a magtape. Two differnet set of prompts are used depending on the transfer mode entered at this prompt. .literal ENTER TRANSFER MODE: .end literal The acceptable inputs are: .list .le; 0 if the user wishes to read an IBM magtape. .le; 1 if the user wishes to write an IBM magtape. .le; _^Z if the user wishes to exit the utility. .end list .page .subtitle Selecting the magtape drive .paragraph The second prompt is always the magtape drive select prompt. This prompt makes known to the utility which magtape drive it is supposed to use. The magtape of interest should be mounted foreign on the magtape drive before the utitly is invoked. .literal ENTER MAGTAPE UNIT NUMBER: .end literal The acceptable inputs are any of the legal magtape drive names (ie. MTA1, MTA2, etc.) on the system. It should be the same as the magtape drive name entered in the MOUNT command. .paragraph Following the first two prompts above (which always appear irregardless of the transfer mode) come the transfer mode dependent prompts. That is, a different set of prompts is used depending if the magtape is being read from or being written to. The remaining sections is divided into two parts, each dealing with one set of prompts. .page .subtitle Magtape characteristics in write The magtape written on the Vax system for the IBM system will always has the following characteristics: .list .le;Volume serial number -- user specified or what is originally on the magtape. .le;Dataset id -- user specified. .le;Dataset serial number -- 000000. .le;Creation date -- 00000. .le;Expiration date -- 98003. .le;System code -- blank filled. .le;Record format -- variable length format. .le;Block length -- user specified. .le;Record length -- largest record length in the disk file. .le;Block attribute -- blocked and spanned. .end list .page .subtitle Magtape write dependent prompts .literal CREATE VOLUME LABEL?: .end literal This prompt is required due to the two types of magtape the user can use to run with the utility. .list .le;Magtape which already has a volume label already. (ie. all IBM cataloged magtapes will have volume labels already on them). .le;Magtape which does not have a volume label. (ie. a brand new magtape). .end list The acceptable inputs to this prompt is either a YES or a NO. If the user responds with a YES, then the following prompts will appear, however, if a NO is entered, the next prompt will not appear. .literal ENTER VOLUME SERIAL NUMBER: .end literal The acceptable inputs to this prompt is any 6-digit number which serves as the serial number of the magtape. The 6-digit number will be written onto the magtape volume label. The user is adviced to remember this number since he or she may need it on the IBM side to read the magtape. .literal ENTER DATASET ID: .end literal This prompt makes known to the utility the dataset name which it is going to write to the magtape. The dataset name is written onto magtape header label. It is pointed out that the dataset id does not necessarily have to be the same as the input file name. The acceptable inputs to this prompt is any alpha-numeric (up to 17 characters - null padded) string. .literal ENTER MAGTAPE BLOCK SIZE: .end literal The bigger the block size is written to the magtape, the smaller the amount of magtape is used to write the same amount of data. However, it is recommended the largest block size to be used should be around 4000. Using any larger block size may use lesser amount of magtape, but may cause system complications at run-time. The acceptable inputs to this prompt is a number between 20 and 32768. .literal ENTER VAX INPUT FILE NAME: .end literal This prompt makes known to the utility the Ascii disk file that the user wishes to copy onto the magtape. The acceptable inputs to this prompt is any legal filespec of the Vax system. .paragraph After the input to the last prompt, the utility will begin to copy the disk file onto the magtape. This utility is capable of handling multiple dataset, mutiple volume magtape format. When the utility finishes processing the current disk file, it will prompt again for the next disk file to copy onto the magtape by prompting for the dataset id. If the user has more disk file to copy onto the magtape, he can follow the above sequence again. if the user has no more files to copy onto the magtape, the user should enter _^Z to exit the utility (an end of volume label is written onto the magtape in the exting process). Entering _^Z will cause the utility to terminate and the DCL command level to prompt. When the utility terminates, the magtape will automatically rewind to its BOT point. The user should dismount the magtape by using the DISMOUNT command. .literal $ DISMOUNT MTA1 .end literal .page .subtitle Magtape characteristics in read The IBM magtape being read should have the following characteristics in order for the utility to perform successfully: .list .le;Record format -- variable or fix length format. .le;Block attribute -- blocked (spanned or not-spanned). .end list .page .subtitle Magtape read dependent prompts After the magtape drive select prompt, the utility will actually read the magtape lead labels and display its info on the screen. The user after seeing the displayed info (volume serial number, dataset id, etc.) can either continue by responding to further prompts or entering _^Z to exit the utility (if the wrong magtape is mounted, ie.). The displayed info allows the user to double check that he has the correct magtape. .literal ENTER ESTIMATED FILE SIZE IN BLOCKS: .end literal This prompt is here due to the fact that it is much more efficient to allocate the storage for a file once than it is to allocate it many times. So if the user knows the approximate size of the file, he or she can enter the size at this prompt to allocate this storage just once. The acceptable inputs to this prompt is any number between 0 and 32768. .literal ENTER EXTENSION FILE SIZE IN BLOCKS: .end literal For the same reson as above, that is, efficiency, it is desirable to allocate extension file size in big enough chunks so that the system does not has to extend the file many times (if it has to be extended, due to under estimated file size in the above prompt). The acceptable inputs to this prompt is any number between 0 and 32768. .literal ENTER VAX OUTPUT FILE NAME: .end literal This prompt makes known to the utility the file name of the output file the utility should write into. The acceptable inputs to this prompt is any legal filespec in the Vax system. .paragraph The utility supports multiple dataset, multiple volume format. Therefore, if the IBM magtape has more than one dataset on it, then the utility, when it finishes processing the first dataset, will again prompt for the estimated file size, extension size, and the output file name for the next dataset. The user can terminate the utility at any time by entering _^Z as the reponse to a prompt. If the utility detects an end of volume label, it will automatically terminate. When the utility terminates, it will rewind the magtape to its BOT point. The user should dismount the magtape by using the DISMOUNT command. .literal $ DISMOUNT MTA1 .end literal