line disk storage for spectral libraries to aid in interpretation and for archi val storage. After benchmarking the interactive requirements, a dual Harris S200 sys tem with shared disk was installed in late 1977. The present system consists of a dual CPU Harris H-800 system with shared memory and 900 mega bytes of shared disk (Figure 4). Pres ently about 20 instruments are inter faced to the system. Users communi cate with the system via about 50 ter minals, including 13 Tektronix 4014 high-resolution graphics terminals with graphic input tablets. Four Ver-
satec printer/plotters located in labo ratories and a Calcomp plotter in the computer room provide hard-copy graphics output. Graphics program ming is done using a locally developed graphics subroutine package, based on the SIGGRAPH standard, which allows for device-independent graphics pro gramming, i.e., the same program can be written for any of the four different graphics devices currently on the sys tem. A set of sophisticated operating system extensions has been developed to support real-time data acquisition, including the digital input, analog input, and digital output functions
THE ULTIMATE BLACK BOX HAS ARRIVED! Introducing the intelligent interface. A new concept in interfacing laboratory analog signals to your computer. Programmable in any language for any CPU fhaf s RS 232C or IEEE 448 compatible. Extremely high, 20-bit precision, with a dynamic range of ΙΟ6. Totally controlled from your computer. No knobs, dials or switches Once triggered at the be ginning of a data acquisition sequence, a 760 or 860 Series Interface will store data in its memory until Ihe run's end, up to 6 4 , 0 0 0 bytes or 3 0 . 0 0 0 points of data. Remote start plus eight external events, all at prices between $1800 and $24CO. Call or write us today at 20370 Town Center t ane, Cupertino, CA 95Q14. (408) 725-Π07
NELSON ANALYTICAL
CIRCLE 155 ON READER SERVICE CARD 1306 A · ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982
used in most of the data acquisition activities. The system is currently supported by one systems programmer, one ap plications programmer, a resident Harris service engineer, and part-time efforts of two other people. There is no computer operator. For applica tion-specific programs, users usually do their own programming; for subsys tems that span across applications, programming support is provided. Roughly half of the plans that we have for the system are currently im plemented and operational. We have found the system to be very powerful and very reliable, with a high uptime. It performs all functions very well. Building on the success of our dual CPU Harris system, we have recently installed a Harris H-500 system, using the same software as the system dis cussed above, to support the needs of our Drug Metabolism Research Unit (about 50 research personnel), requir ing two additional programmers. This system, located in a different building, supports several dozen gas and liquid chromatographs, including many with automatic injection systems; several balances; and several liquid scintilla tion counters. The transfer of software between the dual H-800 system and the H-500 system was accomplished very smoothly. Since balances and chromatographs are supported on both systems, the savings on software have been great. We have also recently acquired a Harris H-300 system to support high-performance color graphics for use in drug design and molecular modeling activities. Again the same operating system is used. We estimate that the H-500 and the dual H-800 laboratory automation systems are equivalent to approxi mately 50 additional personnel in terms of additional output from the units supported. Using a central super-mini approach to laboratory au tomation has saved us much in shared peripheral devices, ease of program ming, cost of programming, and mainte nance support. We have a very power ful system, which each user looks to as his or her own. Major goals for the sys tem have been to provide good soft ware documentation and acceptable audit trails for data and software ma nipulation, as well as to provide sim ple and reliable backup. These are tasks difficult to handle adequately on distributed computers. The disadvan tages of the central approach are the high initial cost, the need to have a very capable systems programmer to make it work well, and the fact that all instrumentation is dependent upon a single computer system. In our experi ence, however, these disadvantages have been far outweighed by the ad vantages mentioned above.
