Tape Cartridges Research Articles

Managing data recovery for Long Term Data Preservation

In the latest years, CNAF worked at a project of Long Term Data Preservation (LTDP) for the CDF experiment, that ran at Fermilab after 1985. A part of this project has the goal of archiving data produced during Run I into recent and reliable storage devices, in order to preserve their availability for further access through not obsolete technologies. In this paper, we report and explain the work done to manage the process of retrieving the aforementioned data, which were stored into about four thousands 2.5/5GB 8mm tape cartridges of different producers, which were widely popular in the nineties. The hardware setup for tape reading is briefly detailed. Particular focus is on describing in-house software tools and backend database that have been set up to drive and orchestrate the tape readers and to deal with the high number of possible problems arising during the process of reading data from hardly reliable media. The outcome of each operation is accounted into the database, making possible to monitor the overall progress and to retry unsuccessful read attempts at a later stage. The implemented solution has proved effective at reading a first 20% of the total amount. The process is currently ongoing. Even though a few aspects of this work are strictly dependant on how the CDF experiment organized its datasets, we believe that several decisions taken and the overall organization still make sense on a variety of use cases, where a relevant amount of data has to be retrieved from obsolete media.

Last developments of the INFN CNAF Long Term Data Preservation (LTDP) project: the CDF data recover and safekeeping

The INFN CNAF Tier-1 has become the Italian national data center for the INFN computing activities since 2005. As one of the reference sites for data storage and computing provider in the High Energy Physics (HEP) community it offers resources to all the four LHC experiments and many other HEP and non-HEP collaborations. The CDF experiment has used the INFN Tier-1 resources for many years and, after the end of data taking in 2011, it faced the challenge to both preserve the large amount of scientific data produced and give the possibility to access and reuse the whole information in the future using the specific computing model. For this reason starting from the end of 2012 the CDF Italian collaboration, together with the INFN CNAF and Fermilab (FNAL), introduced a Long Term Data Preservation (LTDP) project with the purpose of preserving and sharing all the CDF data and the related analysis framework and knowledge. This is particularly challenging since part of the software releases is no longer supported and the amount of data to be preserved is rather large. The first objective of the collaboration was the copy of all the CDF RUN-2 raw data and user level ntuples (about 4 PB) from FNAL to the INFN CNAF tape library backend using a dedicated network link. This task was successfully accomplished during the last years and, in addition, a system to implement regular integrity check of data has been developed. This system ensures that all the data are completely accessible and it can automatically retrieve an identical copy of problematic or corrupted file from the original dataset at FNAL. The setup of a dedicated software framework, which allows users to access and analyse the data with the complete CDF analysis chain, was also carried out with the addition of users and system administrators detailed documentation for the long-term future. Furthermore a second and more ambitious objective emerged during 2016 with a feasibility study for reading the first CDF RUN-1 dataset now stored as an unique copy in a huge amount (about 4000) of old Exabyte tape cartridges. With the installation of compatible refurbished tape drive autoloaders an initial test bed was completed and the first phase of the Exabyte tapes reading activity started. In the present article, we will illustrate the state of the art of the LTDP project with a particular attention to the technical solutions adopted in order to store and maintain the CDF data and the analysis framework, and to overcome the issues that have arisen during the recent activities. The CDF model could also prove useful for designing new data preservation projects for other experiments or use cases.

Moore’s law realities for recording systems and memory storage components: HDD, tape, NAND, and optical

This paper describes trends in the storage technologies associated with Linear Tape Open (LTO) Tape cartridges, hard disk drives (HDD), and NAND Flash based storage devices including solid-state drives (SSD). This technology discussion centers on the relationship between cost/bit and bit density and, specifically on how the Moore’s Law perception that areal density doubling and cost/bit halving every two years is no longer being achieved for storage based components. This observation and a Moore’s Law Discussion are demonstrated with data from 9-year storage technology trends, assembled from publically available industry reporting sources.

Volumetric density trends (TB/in.3) for storage components: TAPE, hard disk drives, NAND, and Blu-ray

Memory storage components, i.e., hard disk drives, tape cartridges, solid state drives using Flash NAND chips, and now optical cartridges using Blu-ray disks, have provided annual increases in memory capacity by decreasing the area of the memory cell associated with the technology of these components. The ability to reduce bit cell sizes is now being limited by nano-technology physics so that in order for component manufacturers to continue to increase component capacity, volumetric enhancements to the storage component are now being introduced. Volumetric enhancements include adding more tape per cartridge, more disk platters per drive, and more layers of memory cells on the silicon NAND substrate or on the optical disk substrate. This paper describes these volumetric strategies, projects density trends at the bit cell level, and projects volumetric trends at the component level in order to forecast future component capacity trends.

Adaptive Regulation of Time Varying Disturbances in a Tape Storage System

Archival demands for digital tape storage systems require smaller spacing between data tracks on the magnetic tape to allow for more data storage on a single cartridge. Increasing track density while maintaining track following provides a challenge for the servo control of the tape drive. In particular, interchangeable tape cartridges and time-varying tape reel diameters during operation cause variable disturbances during servo control. In this paper we show how a tape servo control algorithm can be regulated to handle changes in disturbance dynamics during servo operation of the tape drive. The approach is based on adaptive regulation by exploiting a Youla-Kucera parameterization of the servo controller and an explicit minimization of the Position Error Signal (PES) during servo operation in real-time. Theoretical results on the stability of the feedback system and real-time application results on an Linear Tape-Open (LTO) drive are included in the paper. The result show a significant reduction of the variance of the PES over different tape cartridges and a constant PES variance during a complete reel-in operation of the tape drive.

Servo-Pattern Design and Track-Following Control for Nanometer Head Positioning on Flexible Tape Media

Achieving multi-Terabyte capacity in tape cartridges requires a substantially higher track density than that available in present systems, and hence a significantly higher positioning accuracy is required of the track-following servo in tape drives. In this paper, advanced concepts are considered for several elements of a tape system that enhance the track-following servo performance to reach nanometer positioning accuracy. We introduce a novel method for optimizing the geometry of servo patterns in a timing-based servo system. The design criterion aims to minimize the measurement error in the position-error signal (PES) yielded by a digital synchronous servo channel. A flangeless tape path is adopted to mitigate high-frequency components of the lateral tape motion. The track-following servo controller, which is designed based on the H∞ approach, takes into account the measured plant transfer function, the disturbance characteristics of the tape path, and the properties of servo channel. These elements are combined to investigate the track-following performance achievable with a new high-SNR magnetic tape based on perpendicularly-oriented BaFe particles. With this setup, a record closed-loop track-following performance of less than 14 nm PES standard deviation is demonstrated.

Magnetic Tape for Data Storage: An Enduring Technology

Magnetic tape as used for data storage is reviewed. Attributes such as bit and track densities, tape cartridge capacities and data rates are discussed in terms of the growth seen over time together with future trends envisioned for tape. Tape has seen almost six orders of magnitude density increase since its introduction as a computer data storage device in the early 1950's with 1 Terabyte native capacity tape cartridges being introduced into the market. The recording methods and technologies used for tape data storage devices are outlined and tapes position in the storage landscape discussed. Most of the world's data is stored and archived on magnetic tape primarily because of its long shelf life and favorable cost factors.

Effects of varying operating tension and speed on lateral tape motion in MP and AME tapes using magnetic signal and optical probe methods

The drive for increased storage capacity in today's magnetic tape cartridges has created a continuing need to improve the understanding of the tribological performance of magnetic tape. One important area of ongoing tribological research is lateral tape motion (LTM). The importance of studying LTM will only continue to grow, as the demands for more storage capacity move forward. One particular area of interest with regard to LTM is to determine the effects of the operating tension and speed on LTM generation. As such, this study focuses on LTM in six different tape samples when the operating tension and speed are varied. The tapes studied include metal particulate (MP), Thin MP, and four advanced metal evaporated (AME) tapes. A new technique based on the readback of a written magnetic signal was used in making LTM measurements. The results from the new method are compared to the results from the optical probe method used frequently in the past. Mechanisms responsible for the observed trends are discussed.

Contact pressure effects on pole tip recession and head stain in linear digital tape systems

Linear Tape Open (LTO) and Travan5 heads were tested against the exactly similar formulation metal particles tape loaded into appropriate cartridges at a range of controlled environmental conditions. These tape cartridges were produced specifically for this study by the Imation Corp. Optical Microscopy was used to identify the head stains and debris distribution. Atomic force microscopy (AFM) was used to analyse the changes in surface topography of the heads and Auger electron spectroscopy (AES) was employed to analyse the chemical changes on the surface of the heads after up to 5000 passes of tapes. Conventional Fe based stain was seen to form on the heads of each tape format for all conditions with the exception of Travan5 heads at 40 °C and 80% relative humidity (RH) which were covered with much thicker and more extensive polymer based stain. The Travan5 heads showed a much greater propensity to stain than LTO heads. Pole tip recession (PTR) of the LTO heads was lower than Travan5 heads after cycling for the same distance and in the same environment condition. Higher temperature and higher humidity lead to higher PTR in each system. The contact pressure between the LTO head and tape is much lower than the Travan5 system (around one-third) and this the major factor for the reduced stains and lesser PTR value in the LTO system. The reduced contact pressure not only reduces the number of the three-body particles production, but also reduces chemical effects responsible for PTR and stain. X-ray photoelectron spectroscopy (XPS) was used to identify the chemical changes that occurred at the media surface. This showed that in all areas of the tape, the amount of detected Fe had slightly increased, whilst the N signal (an indicator of polymeric binder) had decreased. No significant tape wear occurred in either the LTO or Travan5 systems. The roughness (RMS measured by AFM) of the tape did not change significantly after cycling in either system, with the exception of Travan5 tapes cycled at the 40 °C, 80% RH which showed an increase. The more tape debris present on the Travan5 heads comparing with LTO heads. The results indicate conclusively that reduced contact pressure is responsible for the reduction in both stain and PTR.

Electronic Records Management (ERM) Electronic Government (E-Gov) Initiative Transferring Permanent Electronic Records to the National Archives of the United States

OMB E-Gov InitiativeNARA is working with the Office of Management and Budget (OMB) to implement the President's Management Agenda for expanding electronic government. The President's E-Government Strategy is engaged in 24 government-wide initiatives to integrate agency operations and information technology investments. The goal of these initiatives is to eliminate redundant systems and significantly improve the government's quality of customer service for citizens and businesses through a variety of E-Gov Initiatives. This will ultimately make it simpler for citizens to receive high-quality service from the Federal Government, while reducing the cost of delivering those services.NARA is the managing partner of one of these 24 initiatives, entitled E-Government Electronic Records Management (E-Gov, ERM) Initiative. This initiative will provide the tools that agencies will need to manage their records in electronic form, addressing specific areas of electronic records management where agencies are having major difficulties.The projects that are part of the ERM Initiative are organized into four issue areas, each with a lead Federal agency. Of the four issue areas, NARA is the lead agency on the issue area relating to the transfer of permanent records to NARA (i.e., issue area 4). Issue area 4 focuses on the transfer of electronic records in formats not previously accepted by NARA. The articulated goal is: “to provide the tools for agencies to access electronic records for as long as required and to transfer permanent electronic records to NARA for preservation and future use by government and citizens.” This paper discusses the process, products, and lessons learned in issue area 4.Issue area 4, Transfer of Permanent E-records to NARA expands both the number of formats NARA can accept, and the media and techniques that can be used by Federal agencies when transferring their permanently valuable electronic records to the National Archives of the United States.This project has three major components that will facilitate the transfer of electronic records to the National Archives for preservation and future use by Government and citizens.Additional Transfer MechanismsBefore the Electronic Records Management Initiative, NARA regulations specified that agencies transfer permanent electronic records to the National Archives of the United States via open-reel magnetic tape, 3480-class tape cartridges, and CD-ROM. As part of the Initiative, NARA revised its regulation, effective January 29, 2003, to expand the transfer methods to include higher density DLT tape media and media-less File Transfer Protocol. http://www.archives.gov/about_us/regulations/part_1228_l.htmlMetadata and XML Schema ProjectThe objectives of the Records Management Metadata and Schema Project were to identify the metadata needed to transfer electronic records to NARA and to create the XML schema to encapsulate those metadata elements. This XML records transfer schema was completed and registered in a Federal repository in June 2003.Additional Transfer FormatsNARA and partner agencies identified six priority records electronic formats for NARA to use in developing transfer guidance. These formats include:• Email with attachments (issue date September 30, 2002),• Scanned Textual Images (issue date December 23, 2003)• Portable Document Format (PDF) (issue date March 31, 2003),• Digital Photography (issue date November 12, 2003)• Digital Geospatial Records (issue date April 15, 2004)• Web Based Records (issue date September 17, 2004)This paper describes the collaborative process NARA is using to work with Federal agencies in accomplishing the goals of issue area 4, it provides examples of records transfer guidance issued by NARA, and discusses lessons learned.

Strategic directions in storage I/O issues in large-scale computing

—rigid or hard magnetic disks; —parallel disk arrays; —optical disks, which have several variants: read-only [such as CD-ROM and digital video disk (DVD)], write-once (WORM), and rewritable (magnetooptical or phase change); —magnetic tape, such as 4mm (DAT), 8mm, and digital linear tape (DLT); —autochangers, which combine storage devices with racks of tape cartridges or optical disk platters that can be moved to and from the drives by robotics. —Complete storage systems also include software to manage and orchestrate the storage components. Such software includes management and configuration utilities for storage devices, logical volume managers that tie multiple physical devices together as one, and file systems to arrange layout of data on storage devices. —Storage systems are a vital and growing market. Their primary components are magnetic and optical disk drives, magnetic tapes, and largecapacity robotic assemblies of drives and cartridges. Storage hardware sales in 1995 topped $40 billion, including more than 60,000 terabytes of hard disk storage. In recent years, the amount of storage sold has been almost doubling each year; in the near future it is expected to sustain an annual growth of about 60%. This enormous growth rate has been accompanied by a 50% per year decrease in the cost per byte of storage. These growth trends exceed those of the personal computer market. —The focus of this article is on secondary storage systems and primarily on magnetic disk drives, since these are

Integrating mass spectrometry data systems from different manufacturers in a local area network

Several scientific instruments suppliers are offering complete networking and automation packages for analytical laboratories. Nevertheless there is still considerable work to be done in the area of standardization of file formats generated by different data acquisition systems supplied by scientific instruments manufacturers. Recent work on the netCDF transfer protocol for mass spectrometry data suggests that good progress is being made in the area of data formats. Our laboratory operates a number of diverse instruments, including two high resolution systems (ZAB 2F, 70 SEQ) and one quadrupole (QMD 1000) from Fisons Instruments, one ion trap system from Finnigan (ITS 40) and one pyrolysis mass spectrometer from Horizon Instruments (RAPyD-400), all equipped with autosamplers. This instruments are physically located in two distinct laboratories. The data systems are based on very different computers, including a DEC PDP-11/24, a VAX 4000/90 and several PCs. The large amount of data produced by the MS laboratory and the implementation of GLPs, (Good Laboratory Practices) and GALPs (Good Automated Laboratory Practices) prompted us to examine the possibility of networking the instrumentation in a client/server computing environment. All instrument data systems have been connected to the institute network via ethernet, using either DECnet or TCP/IP. A VAXCluster consisting in a VAXStation 4000/90 host and a VAXStation 3100 satellite has been configured as a server using DEC PATHWORKS V.4.1 server software. This allows for file, disk, application and print services to all the PC clients connected network wide. Unattended distributed backup and restore services for PC hard disks are implemented. Mass spectrometry data files are permanently archived in their original format on 4 Gbyte tape cartridges and stored for later retrieval. Files can be transferred to any office PC running the appropriate mass spectrometry software. A centralized spectra and structure information management system based on the MassLib (Chemical Concepts) software allows for library searches using the SISCOM algorithm after specific file conversion programs or using JCAMP-DX files. Furthermore, the mass spectrometer data systems are readied for their eventual incorporation into a LIMS.

Integrating mass spectrometry data systems from different manufacturers in a local area network

Several scientific instruments suppliers are offering complete networking and automation packages for analytical laboratories. Nevertheless there is still considerable work to be done in the area of standardization of file formats generated by different data acquisition systems supplied by scientific instruments manufacturers. Recent work on the netCDF transfer protocol for mass spectrometry data suggests that good progress is being made in the area of data formats.Our laboratory operates a number of diverse instruments, including two high resolution systems (ZAB 2F, 70 SEQ) and one quadrupole (QMD 1000) from Fisons Instruments, one ion trap system from Finnigan (ITS 40) and one pyrolysis mass spectrometer from Horizon Instruments (RAPyD-400), all equipped with autosamplers. This instruments are physically located in two distinct laboratories. The data systems are based on very different computers, including a DEC PDP-11/24, a VAX 4000/90 and several PCs.The large amount of data produced by the MS laboratory and the implementation of GLPs, (Good Laboratory Practices) and GALPs (Good Automated Laboratory Practices) prompted us to examine the possibility of networking the instrumentation in a client/server computing environment. All instrument data systems have been connected to the institute network via ethernet, using either DECnet or TCP/IP. A VAXCluster consisting in a VAXStation 4000/90 host and a VAXStation 3100 satellite has been configured as a server using DEC PATHWORKS V.4.1 server software. This allows for file, disk, application and print services to all the PC clients connected network wide. Unattended distributed backup and restore services for PC hard disks are implemented. Mass spectrometry data files are permanently archived in their original format on 4 Gbyte tape cartridges and stored for later retrieval. Files can be transferred to any office PC running the appropriate mass spectrometry software. A centralized spectra and structure information management system based on the MassLib (Chemical Concepts) software allows for library searches using the SISCOM algorithm after specific file conversion programs or using JCAMP-DX files. Furthermore, the mass spectrometer data systems are readied for their eventual incorporation into a LIMS.

TERRAscope and CUBE project at Caltech

The TERRAscope project of the California Institute of Technology began in 1988 and now has six very broadband seismic stations (PAS, GSC, PFO, SBC, ISA, and SVD) in southern California (Figure 1). The goal of TERRAscope is to provide high‐quality broadband data needed for significant advances in both regional and global seismology. TERRAscope will replace the old Caltech seismographic network in southern California, which dates back to the 1920s. In many cases, new stations are deployed in cooperation with local institutions. The goal is to encourage involvement of both students and researchers in the operation of the stations and analysis of new data. The station PAS is a joint project between Caltech, the University of Southern California, the U.S. Geological Survey (USGS), and the Incorporated Research Institutions for Seismology (IRIS). The station SBC was deployed in cooperation with the University of California at Santa Barbara. The station PFO is operated jointly with the University of California at San Diego, and the station SVD was installed and is operated by the USGS. Except for SVD, all of the stations are equipped with a broadband Streckeisen STS‐1 seismometer and Quanterra data logger with a 24‐bit digitizer and a Kinemetrics FBA‐23 strong‐motion sensor. The station SVD has a Streckeisen STS‐2 seismometer and a Guralp CMG‐5 accelerograph. The project is funded mainly by grants from the L. K. Whittier Foundation and the Arco Foundation. In addition to the automatic dial‐up data retrieving system called Caltech Gopher (adapted from the IRIS Gopher system) has been implemented. The Caltech Gopher receives mail from NEIC for teleseisms and the SCSN with origin time, location, and magnitude for regional events. The Gopher retrieves data from all six TERRAscope stations for these events. The TERRAscope data reside in an FTP anonymous account (seismo.gps.caltech.edu; password: “your e‐mail address”) at the Caltech Seismological Laboratory, and are available to users through Internet. Usually the data are available within 30 minutes after a regional event and several hours after a teleseism. In the near future a new version of the Gopher software will be installed, which will also make some of the Gopher data available directly from the IRIS‐DMC Gopher. When the Data Center of the Southern California Earthquake Center begins full operation in early 1992, it will take over the distribution of earthquake data from southern California, including both TERRAscope Gopher data and continuous data from the tape cartridges. The data will also be available from IRIS‐DMC, and future improvements and changes in data access will be posted on the IRIS‐DMC bulletin board.

Archival stability of IBM 3480/3490 cartridge tapes

The IBM 3480/3490 cartridge tape established a new format for digital data recording. Increased data rate and capacity compared to reel-to-reel digital tape technology was achieved along with a considerable reduction in the size and cost. Methods for the archival storage of magnetic tapes are discussed. The importance of proper binder selection to minimize chemical-degradation-induced deterioration of tape performance is reviewed briefly. In addition, the mechanical attributes of a magnetic coating required to minimize the friction, distortion, and detrimental effects of stress relaxation during long periods of storage are described. The importance of acquiring a detailed knowledge of the operable mechanisms that impact tape performance and the relevance of accelerated aging studies is emphasized. The design features of the 3480/3490 magnetic tape subsystems that improve its toleration of tape deficiencies are discussed. The mechanisms of failure to which these tape subsystems are ultimately vulnerable are then used to recommend procedures and conditions for optimum storage of recorded tape cartridges.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Digital recording of seismic data on magnetic tape cartridges under microcomputer control

The quantity of digital data which needs to be managed both in the field and in the processing centre causes handling and storage difficulties in the course of modern marine seismic acquisition and processing. Within the industry generally, the physical bulk of the recording medium has been reduced by use of the 6250-bpi computer tape format but this involves expensive tape drives and only goes part way to solving the problem in the field.

Interactive computer processing and interpretation of pumping test data. A Micro-computer program using dynamic graphics

This paper presents a computer program for analysing pumping test data. The program is interactive and may be used with a minimum knowledge of computers. It can be applied to a wide range of transient problem types, from one dimensional groundwater flow to flow in anisotropic aquifers, horizontally as well as vertically. Various forms of type curves based on analytical solutions to the groundwater flow equation are available for the interpretation. The paper includes a listing of the entire computer program containing a total of about 1. 800 lines. The programming language is a BASIC-version suited for the Tektronix 4054, a graphic screen with a refresh option. This option allows the user to perform type curve matching directly on the screen by moving the chosen type curve to the position where it gives the best fit, in a manner similar to traditional manual chart interpretation. Plots of the measured data may be conveniently reproduced in semilog and log-log diagrams, either on the screen or as a hard copy printed by a plotter. The present version of the program makes use of tape cartridges, both for storing program and data files.

A simple microcomputer-based three-dimensional serial section reconstruction system (MICROS)

We have developed a computer system which enters and aligns serial sections and displays the completed reconstructions at different rotations in space. The system uses commercially available hardware, including a Hewlett-Packard 9845T microcomputer and an H-P 9874A digitizer. The software for the system is written in the BASIC language. The system consists of two programs, one for section digitization, the other for rotation and display of the reconstructions. Sections are digitized directly from micrographs or back-projected slides. The outlines of cells or other structures are traced from these media using a hand-held cursor on the digitizer. The positions of elements (inputs) which contact the structure and fiducials are also digitized. The sections are aligned by simultaneously displaying two consecutive sections on the graphics CRT screen. The sections are coarsely superimposed by centering around screen center using a centering algorithm. They are precisely aligned by rotating and translating the images with a reference cursor. Special functions for inserting and deleting sections and rapid section scanning are available for editing. The aligned sections are stored using a linked-list file structure on either floppy disks or tape cartridges. The rotation program replots the completed reconstructions on the graphics CRT or digital plotter. The program will reproduce the reconstructions at any scale and at any rotation in the x-, y- or z-planes. A hidden line algorithm removes hidden lines to give a 3-dimensional (3-D) perspective to the reconstructions. The positions of inputs and fiducials are represented by symbols. We use the system to reconstruct cells and neural processes. The 3-D reconstructions allow us to: (a) examine the spatial distribution and density of synaptic contacts on neurons; (b) study complex neuronal shapes; (c) examine the vectors of neural processes. The computer reconstruction system, which is moderately priced, should also prove useful for reconstructing many other types of biological profile.

Developments in the SL-10 Packet Switch: Resource, File, and Software Loading Management

The Northern Telecom SL-10 Packet Switching System is steadily enhanced to provide better access services for users. Equally important to them, but less visible, are enhancements to improve availability and increase throughput. To this end, intelligent peripheral devices, such as storage controllers and line servers, have been added to the Switch and new strategies, especially for software loading, have been devised. Such additions have had an impact on the software architecture. The Resource Subsystem now has to cope with a wider variety of devices, including intelligent peripheral devices. The File Subsystem has been generalized to accommodate files on different types of volumes, e.g., disks and tape cartridges. A whole new Subsystem has evolved to handle strategies for loading processors in parallel and to load intelligent peripherals. The SL-10 Packet Switch software architecture, with its process environment structured in Subsystems, has proven well suited to these requirements.

Design and applications of a microprocessor-controlled system to optimiz preparative liquid chromatography

A microprecessor-controlled instrument, able to piot pumps, solenoid valves, fraction collectors as well as any other electrical appliances, was designed to improve the efficiency of our preparative liquid chromatography equipment. Facilities to select buffers, load samples, generate linear gradients and modulate the programmed elution processes by positiv feed-back interaction with up to eight on-line detectors were included in the software. As many as 50 consecutive instructions may be programmed as simple coded mnemonics and executed on the 16 parallel output lines with respect to actual time and/or external feed-back signals. Sets of instructions may be stored on tape cartridges using a normal tape-deck. The main improvements brought about by use of this technology are greater reproductivity of elution patterns an improved resolution of the detected peaks. An application to the fractionation of protein from human serum is described and differences between methods are discussed.