Mini Computers

Computers. A certain number of personal computers are necessary for report generation and regulatory submission preparation. In addition, these may be useful for record keeping, depending on the type of stability information system that the company chooses to use. Alternatively, if the information system is intended to be accessible (read only) to many users, it may be more efficient to develop a local area network of mini-computers. The size of the database will help determine the nature of the software/hardware configuration used for this function. 

Photon correlation spectroscopy (P.C.S.). this was used as an alternative method of determining particle diameters from derived diffusion coefficients. The instrumentation consisted of a Coherent Kr ion laser (CR 2000K), plus a Malvern Instruments PCS 100 set up, linked to a Malvern Instruments multibit correlator (K7025) data was analysed using an on-line Apple II mini computer. 

One development that has affected bakery equipment is the microprocessor revolution. The availability of cheap computing power has seen mechanical controls superseded by electromechanical controls to be replaced by electronic controls. It is now possible for an entire bakery to be controlled by one ruggedised microcomputer. This is a considerable cost reduction compared with the mini computer that would have been required previously. 

Portability. RuleMaster is written in the C language, making it portable to a wide range of micro- and mini-computers with the UNIX, VMS, or PC-DOS operating systems. By late 1985 RuleMaster had been installed on more than twenty brands of computers, ranging in size from IBM PCs to large mini-computers. 

Fig. 2.10 Schematic representation of a system with several units for automation of basic operations, controlled by a mini-computer.

Samples are injected into the vaporizer by a metering pump or manually with septum injection the manual injection procedure is intended for method development. The sample gas mixture then passes through the chromatographic column where the sample compounds separate. Fractions pass through the thermal conductivity detector and then to a condenser collection manifold where up to five fractions can be collected. Complete control of the system is achieved via a mini-computer. 

The late 1960s saw the appearance of dedicated laboratory mini-computers and the third generation of instrument systems (Fig. 8.4). The computers were interfaced to existing instruments and were used primarily to log and process data. In some cases, simple instructions could be sent to the instrument by programs resident in the minicomputer. It was also possible for the computer to optimize instrument conditions in real time by monitoring output data. 

A continuous capillary viscosity detector has been developed for use in High Performance Gel Permeation Chromatography (HPGPC). This detector has been used in conjunction with a concentration detector (DRI) to provide information on the absolute molecular weight, Mark-Houwink parameters and bulk intrinsic viscosity of polymers down to a molecular weight of about 4000. The detector was tested and used with a Waters Associates Model 150 C ALC/GPC. The combined GPC/Viscometer instrumentation was automated by means of a micro/mini-computer system which permits data acquisition/reduction for each analysis. 

Traditionally, a main frame computer was one that operated using 32 or 64 bit words. A minicomputer was one that utilized a 16 bit word and the microcomputer was one that used a 4 or 8 bit word. However, these distinctions in classifications are very quickly disappearing with the further miniaturization of computers, the increasing speed of microprocessors, and specifically the design of more powerful micro and mini computers. Many of the new microcomputers are far more powerful and capable than what just a few years ago was considered a large main frame system. 

In most applications the low signal levels necessitate the use of signalaveraging techniques. A wide variety of multichannel analyzers, mini computers, and microprocessors suitable for this application are now commercially available. Frequently these devices must issue commands and/or receive information from parts of the spectrometer that are at elevated voltage levels, and this can best be achieved by means of optical coupling. 

The Computer. AXIS is written in FORTRAN and runs on a GEC 4000 series multi-user mini computer equipped with a Graphics Option Controller (GOC) model 5250, manufactured by Sigma Electronic Systems Ltd. This device converts an alphanumeric visual display unit into a graphics terminal, allowing independent use of the alphanumeric and graphics screens. In addition, it provides cursor handling facilities and the ability to selectively erase part of the screen. All of these features are utilised by AXIS. 

An opto-isolated interface is used to couple the MS/EOID to a mini-computer where a new complete spectrum can be taken as often as every 50 milliseconds. With real time decalibration "on-the-fly" complete spectra can be processed every 4.5 seconds. 

For both the subdistribution and the GEX fit methods a Marquardt algorithm for constrained non-linear regression was used to minimize the sum of squares error (.10). The FORTRAN program CONTIN was used for the constrained regularization method. All computations were performed on a Harris H-800 super mini computer. 

The major emphasis will be on the minimum variance stochastic control schemes of Box and Jenkins ( b) and Astrom (l ), and on modifications of them. These schemes have seen successful application in the polymer industry, and they are intuitively appealing and yet simple enough to be implemented by the plant operators using either a programmable hand calculator or control charts and tables. More powerful adaptive versions can be implemented if a small online mini-computer is available. 

The second more modern definition describes a Network comprised of more computers tied together with relatively few terminals on each computer. This second form of network became a reality with the mini computer revolution was spurred by acceptance Digitals PDP-8 and PDP-11 Mini computers in the 1960s and development of Digitals Network Architecture (DNA) in the 1970s. In order to clarify the distinction lets call the first form of "network" Data Communications and the second type a Digital Computer Network. 

Computer network infrastructure should be qualified in support of validated applications. Bristol Meyer Squibb have adopted a three-level model to assist the quahfication of their computer network infrastrucmre. This approach is summarized in Table 14.3. Layer 1 comprises computers that provide shared resources such as servers, hosts, mainframes, and mini computers. Layer 2 is the network infrastrucmre (e g., hubs, routers, and switches). Layer 3 comprises the user desktop environment (i.e., workstations, personal computers, and laptops). 

Commercial data systems are now available for all the principal GC-MS instruments although a number of independent centres have developed their own systems to suit individual requirements [44]. These range from low cost off-line systems to dedicated mini computers linked to time-shared central computers. Many of these systems are in advance of commercial packages but the different capabilities of their configurations are outside the scope of this article. (For a review of computerised data acquisition and handling see [45]). However it is useful to consider some of the hardware components and requirements of a small on-line computer system (Figure 1.8) for low resolution GC-MS work. 

Here is how SAL works Samples are received in a reception and storage room, then routed to the appropriate wet chemical analysis laboratory. There, they are analysed for uranium, thorium or plutonium content, and purified aliquots (portions of the sample) are prepared for the isotopic analysis of three elements. Isotopic analyses are performed routinely by mass spectrometry, and radiometric techniques are used for back-up. Emission spectrography serves to detect the presence of impurities which could interfere with the measurements and thus distort the results of the chemical and isotopic analysis of uranium, thorium and plutonium. Complex calculations and quality checks are performed on minicomputers, which are connected in a network to a central laboratory mini-computer. A central laboratory data system stores and provides analytical reports and enables the quality of the analyses and the status of the flow of samples through the laboratory at any time to be monitored. 

Central Processing Unit (CPU) The computing and control part of the computer. The CPU in a mainframe computer may be contained on many printed circuit boards, the CPU in a mini computer may be contained on several boards, and the CPU in a PC is contained in a single extremely powerful microprocessor. 

J. Cooper, The Minicomputer in the Laboratory (John Wiley and Sons, New York, 1977). Even though this book is written in terms of the PDP-11 computer, it is an excellent treatment of software used in FT NMR, as well as mini-computer programming in general. 

The primary function of the computer in FTIR instruments is to perform the Fourier transformation that converts an inter-ferogram to a recognizable spectrum. However, the availability of an on-line mini-computer has opened the door to routine data manipulations. In this section we will review procedures that have been or promise to be useful in coal characterization. Certain data analysis operations, such as numerical integration... 

This approach has been attempted some years ago in the study of reaction kinetics, but at the time on-line mini-computers were not available. The procedure involved obtaining a laborious point-bypoint description of each spectrum which was then used as input to a large computer. Consequently, the method was not actively pursued. The use of FTIR with its on-line computer should theoretically allow us to use this approach to analyze mineral mixture, but at this time the procedure has yet to be adapted. We are presently attempting to develop appropriate programs. 

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