In the previous post I introduced the mainframe server hardware. In this post I will highlight the most common peripherals – other hardware like disk storage, tape and printers.

This post appears as part of a number of articles in the category “Don’t Be Afraid Of The Mainframe.

Mainframe peripherals

There are no hard disks in a mainframe server. This is also the case for some larger x86 servers. In our laptops and PCs, we always have a hard disks – or SSD nowadays – to store our data. Storage of the data for the mainframe is external to the mainframe box. Data is stored in separate equipment, called storage controllers or storage (sub)systems.

A special high-speed network connects a mainframe to its storage. A mainframe needs a lot more disk storage than our laptops. Normal amounts of storage easily exceed 1000 TB.

By the way, a quirky thing: disk storage on the mainframe is often referred to as DASD. This is an old abbreviation for Direct Access Storage Device.

To confuse you further, when mainframers refer to “storage”, they may actually mean memory, the RAM in the box. So be careful with the term storage, and make sure what is meant when it is used.

For backup and archiving of data, many organizations still use storage on tape. Tape units, often including a “library” to register and store the tape cartridges used, are also supplied in separate boxes.

A special fibre-optic network connects the mainframe servers with the storage hardware. For this connection mainframes use a proprietary SAN protocol called FICON.

You may still have printers connected to your mainframe. But you find this not so often anymore. Most printing facilities have been replaced by online applications. Where printing is still needed, this is often done by dedicated printing facilities or printing firms.