In 1987. Bulgarian Telecommunication Company examined the possibility of developing a small computer that can be used for data collection from lab and test equipment working in industrial environment. This determined the choice of membrane keyboard and potential producer - Factory for Sensors and Sensor Devises (ZSSU) in Plovdiv.

Recognizing the complexity of the project, BTC renounces it. The director of ZSSU Slavey Papachev turned for help to the State Committee for Science and Technical Progress (DKNTP) to find a partner and continue the development of the computer. DKNTP suggested a partnership between ZSSU and Research and Production Laboratory "Software" (NIPL "Programno osiguriavane") with director Nedyalko Todorov - a small company at Sofia University formed in late 1984. ZSSU and NIPL agree to jointly develop the computer and the system software. For this purpose, the two companies created "Abacus" Association. Two more companies joined the association - Science and Manufacturing Laboratory "Programme" (NPL "Programa") and the Institute for Nuclear Research and Nuclear Energy. The future computer was called "PALDIN" - old name of the town of Plovdiv. Trade name of the new computer is the property of the Association. Computer "PALDIN" is the first Bulgarian patent pure computer protected copyright for Bulgaria, both the hardware and the software of the system.

NIPL did the functional design of the computer and developed the system software. The computer was designed for two main applications - for training and education market and for control of lab and test equipment working in industrial environment. In order to provide the widest possible market, the computer had a similar interface and full file compatibility with MS-DOS.
ZSSU designed and manufactured the computer. The design group was led by the Director of ZSSU Papachev Slavey, and the following engineers: George Ginov, Ventsislav Gatev, Svetlozar Peychinov and Spas Georgiev. The computer had a bulgarian made SM601 CPU - clone of the Motorola 6800.

Several models of the comuter were developed and implemented in production with the main difference between them being the available graphic modes:

• Paldin - 601


• Paldin - 601A


• Paldin - 601U


• Paldin - 601M


• Paldin - 601T

Some models also have the option to work with standard PC-AT keyboard.

Production began in 1989 and between 1989 and 1992 more than 35,000 computers of different models of "PALDIN" were produced and exported in the USSR.

In early 1992 NIPL started the development of the next generation 32-bit model of the "PALDIN" (the idea was to use the Motorola MC68000 CPU, which is 32 bit processor). The project was terminated in 1992 due to the end of clearing payments between Bulgaria and the USSR.