This thesis describes a system to allow a mass storage device to be installed in a position remote from the computer system which controls it. This system is intended to allow undergraduate students in the Electrical Engineering department at UCT to make use of two nine channel tape drives installed in the undergraduate interfaced to accessed by laboratory for project work. The drives are the department's PDP-11/23 computer, and may be standard operating system directives, as the controller simulates a conventional computer peripheral. The system consists of an SA-Bus based tape transport controller which interfaces to the host computer system via a serial line. The following hardware was designed and built specifically for this system : 1. A CPU card based on the in Tel 80188 microprocessor, incorporating high speed DMA (direct memory access) channels and two interrupt driven serial lines. 2. A timing and control module for the tape transports. This consists of two SA-Bus cards. Two sets of software were written for the system. These are the following : 1. Software to operate the tape controller. This consists of six modules written in Pascal-86 and 8086 assemblers. 2. Software to allow the PDP-11/23 to control the tape drives. This is in the. form of an RSX-11 device driver written in PDP-11 assembler. To allow the particular to proposed local system allow area highly modular form. to be easily the system to network) , the upgraded in the future (in be incorporated into UCT's software was written in an addition to being controlled by a host system in remote mode the tape controller also has the ability to perform a variety of operations in local mode. These include the ability to copy and erase tapes, as well as a comprehensive set of diagnostic functions. When in local operations mode the controller is menu driven, making its use by persons who are not familiar with it quick and easy.

This thesis is divided into two general sections. The first deals with the theory of digital magnetic recording and surveys the more common techniques used in digital magnetic tape recording. A new recording format is described which leads to a greater data rate at normal recording densities. The design and implementation of a recording system using this technique is described. The second section outlines the design of a portable digital recording system compatible with the peripheral unit described in section 1. The application of this system to the acquisition of data from a radioisotope scanner used in nuclear medicine is described and some basic results obtained from the system are demonstrated. Fundamental work towards image enhancement is outlined. / Thesis / Master of Engineering (ME)

Συστήματα μαγνητικών ταινιών χρησιμοποιούνται ευρέως ως μέσα αποθήκευσης και αποκατάστασης δεδομένων. Λόγω του χαμηλού τους κόστους αναλογικά των σκληρών δίσκων συνεχίζουν να προτιμούνται σε μεγάλο πλήθος εφαρμογών όπως δευτερεύουσες συσκευές αποθήκευσης, εγγραφής και επεξεργασίας ηχητικών δεδομένων,βιντεοκάμερες κ.ά. Σε περιπτώσεις όπου θέλουμε να επεξεργαστούμε μια μαγνητοταινία για γρήγορη μεταφορά ή εγγραφή δεδομένων θα πρέπει -η ταινία- να μεταφέρεται σε υψηλή ταχύτητα από το μηχανισμό του συστήματος. Η ταχύτητα αυτή να διατηρείται σταθερή και να βρίσκεται σε συγχρονισμό ε την κεφαλή ανάγνωσης/εγγραφής προς αποφυγή σφαλμάτων μεταφοράς και αναγνώρισης δεδομένων, αναπηδήσεων και χρονικών σφαλμάτων. Σε πιθανά σφάλματα η επαναφορά της ταινίας στο επιθυμητό σημείο αποτελεί τη λύση για την αποκατάσταση του σφάλματος. Η επιτάχυνση και επιβράδυνση που δέχεται η ταινία σε κάθε γρήγορη αναζήτηση δεδομένων προκαλούν τη μεγαλύτερη επιβάρυνση σε αυτή. Ειδικά η συχνή επανατοποθέτηση της ταινίας στο ίδιο ση είο λόγω της βαθμιαίας εξασθένισης του σήματος ανάγνωσης. Σκοπός είναι ο σχεδιασμός ενός μηχανισμού εταφοράς της ταινίας ο οποίος προσφέρει μια ικανοποιητική τάση στην ταινία όπως και ταχύτητα μεταφοράς αυτής. / Optimal control and estimation of a magnetic tape-drive system.

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The purpose of this project was to describe a novel design approach for a digital computer peripheral controller, then design and construct a case study controller. This document consists of three chapters and an appendix. Chapter II presents the design approach chosen; a variation to a design presented by Charles R. Richards in an article published in Electronics magazine. Richards' approach consists of a finite state machine circuitry controlling all the functions of a controller. The variation to Richards' approach consists of considering the various logically independent processes which a controller carries out and assigning control of each process to a separate finite state machine. The appendix contains the documentation of the design and construction of the controller.

The diploma thesis is focused on the design of a backup system to increase the efficiency of working with stored data and increase the security of stored data. The analysis of the current state describes the company itself and also the backup system using the audit portal Zefis.cz. The following part describes the design of a new backup system that focuses on complexity using the cloud, magnetic tapes, and high server availability.

No description available.