Everything About Homebrew ROM Reader Saves Data From A Vintage Minicomputer





Although the computer feels like a relatively new invention, it dates back to the early 1800s. Initially, giant computer machines were made to perform simple calculations. Later as the technology advanced these computers were programmed to perform complex tasks within a few seconds.

No one would have thought when computers would get so advanced compared to their initial years that they would become a part of our daily routine. Computer evolution started with large systems. 

These large systems were for a period of time only used in big companies like NASA, IBM, etc. Then we had light, portable computing machines capable of fitting into small-scale spaces. These computers are known as mid-range or mini computers. Now, we have desktops and laptops in various sizes and shapes that are capable of performing even difficult tasks with ease. 

In case you entered the field of professional computing somewhere between the 1960s to 1970s, then there is a high possibility that you might have worked in one of such minicomputers. The minicomputer was introduced back in August 1965. 

Many of us would have seen the vintage minicomputer image. But today we don’t find such vintage minicomputers around us anymore. Recently, David Lovett stumbled upon an unfinished version of the digital vintage minicomputer that was made somewhere in the 1980s. 

What is a Vintage Minicomputer?

Minicomputers were a group of computers smaller than the gigantic mainframes of the day. They were given a price tag that put them within the affordable range of medium-sized companies and institutions. The term “minicomputer” is often used today. For example, the SPARC from Oracle Corporation, Power ISA from IBM, and Itanium-based systems from Hewlett-Packard or HP enterprise. 

The vintage minicomputer has all the features of a large-size computer and some of them are even more powerful than standard desktops. It has large-size computers features like high storage capacity and high processing power. In addition to this, it had low maintenance costs. All these features gave these minicomputers the ability to handle more tasks than simply routine tasks. 

Physically they were not small machines. But when compared to the mainframe computers, minicomputers did not require a special building to store them or any sort of high-power electrical supply. The power & price of microcomputers, the power of mainframes & servers, and minicomputers are no longer produced.

Homebrew ROM Reader Saves Data of a Vintage Minicomputer

Getting the digital vintage minicomputer that too from the Reagan administration has its risks. One of the major risks that could occur was the chance of forever losing whatever is on the minicomputer’s ROM chips. 

When searching for a ROM reader holding up the various chips proved to be difficult. So David decided to build his own. The work to make his own vintage minicomputer was eased considerably, as he had managed to read one chip in a commercial reader. This gave him a base to compare his circuit against. 

The hardware is a straightforward 12-bit counter made out of a trio cascaded 74LS161s. David even added an Arduino Nano. This would help in providing the clock pulses and also read the information out to the serial port. 

The made-up circuit gave the same results as ROM chips that were read. This means that the results would be valid for the rest of the chips. The breadboard setup was made to support multiple ROM reader pinouts easily. This setup could even read those chips that take -9 volts. No sources know what exactly the data on the ROMs mean, but at least it is backed up now.

Example of Vintage Minicomputer: DEC PDP 11 Vintage Minicomputer

One of the most notable companies among the suppliers of minicomputers was an American company called Digital Equipment Corporation, otherwise popularly known as DEC. Their PDP line of machines once dominated the market. 

The most successful one among the various machines under the PDP batch line was their DEC PDP-11 series. Today they can be found in the ancestry of many electronic products that we take for granted. Many of you might have even this vintage minicomputer image as well. For instance, the first UNIX development in 1969 was carried out on a DEC PDP-7 series line.

These were 16-bit vintage minicomputers that were left out in their product line from their launch somewhere in the 1970s all through to the early 1990s. They were available in a succession of configurations and physical form factors. The famous DEC PDP 11 Vintage minicomputer is of a batch of floor-to-ceiling racks. But they were used as standalone terminal models and desktop models. 

One of these ‘racks’ of the DEC PDP 11 Vintage minicomputer, called PDP 11/03 from the year 1975 has been revived. And it was used to craft the LSIbox, the PDP 11/03 card frame. Huge numbers of such machines were sold in the market. 

There is even a chance that if you are an adult, you might have even encountered one at work. Most people are even unaware of the fact that the supermarket’s receipt, invoice, or even the doctor’s appointment slip in our hand was processed on it.

Over the 20 years lifespan, of course, Digital Equipment Corporation or DEC did not retain the 74 logic-based architecture of the initial model. But successive DEC PDP 11 vintage minicomputer generations featured the greatest integration of their processor. 

By the 1980s it was seeing its peak in the J 11. It is a CMOS microprocessor implementation of a PDP 11/07. This led it to take the form of two integrated circuits mounted on a large 60 pin DIP ceramic wafer of the vintage minicomputer. 

The vintage minicomputer has many impressive features in its instruction set. Especially the DEC PDP 11 Vintage minicomputer. And any additional general registers, only made it much trouble-free to program it when compared to the other earlier models in the DEC PDP series. 

The DEC PDP 11 replaced the PDP 8 in many real-time applications of the series. The ease of programming code in the DEC PDP 11 vintage minicomputer made it pretty famous for simple and general-purpose computing work as well.

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