Cylinder (magnetic disk)
Data kept in storage, such as files on a disk. The upright cylinder drawn for it is the magnetic disk symbol of the 1970 American flowchart standard; the international standard’s own stored-data symbol is a box with curved sides.
How to read it
The upright cylinder comes from the magnetic disk symbol of the American standard ANSI X3.5-1970, drawn taller than it is wide (2/3 by 5/4) with extra curved lines across the top. IBM’s flowcharting manual has a symbol for disk, drum and random access files, used on system flowcharts to show how data is stored.
The international standard, ISO 5807:1985, uses different shapes. Its stored data symbol, for data stored in a form suitable for processing on an unspecified medium, is a box with a convex left side and a concave right side. Its direct access storage symbol, for magnetic disk, drum or flexible disk, is a cylinder lying on its side. The 1970 American standard had the same two shapes: the curved-sided box as online storage and the horizontal cylinder as magnetic drum.
Also searched as: cylinder flowchart, cylinder (magnetic disk) symbol, database cylinder, database symbol flowchart, flowchart cylinder (magnetic disk), stored data symbol.
Look-alikes
A cylinder on its side is ISO 5807’s direct access storage, or the older standards’ magnetic drum. A circle with a short tail at the bottom right is the magnetic tape symbol, which ISO 5807 calls sequential access storage. A Document has a wavy bottom edge.
Differences by standard
The name “stored data” is ISO 5807’s, and in that standard it belongs to the curved-sided box, not the cylinder. The 1970 American standard called the same box online storage, storage under control of the central processing unit.
Read next
- Next in Flowchart symbolsManual inputData typed or entered by hand while the process runs, for example at a keyboard. The symbol is a four-sided shape with a flat bottom and a top edge that slopes up to the right.
- In Data flow diagram symbolsData storeData the system keeps for later, such as a file or database. In Yourdon/DeMarco notation a data store is two horizontal parallel lines; in Gane and Sarson notation it is a rectangle open at one end.
More flowchart symbols
The same shape elsewhere
Browse symbols drawn with circles or curves and waves.
Sources
- Flowchart Symbols and Their Usage in Information Processing, ANSI X3.5-1970, adopted for federal use as FIPS PUB 24, American National Standards Institute; National Bureau of Standards (NIST), Sections 2, 3.3.1.2, 3.3.1.5 and 3.3.1.6 (shapes from the figures)
- Information processing: Documentation symbols and conventions for data, program and system flowcharts, program network charts and system resources charts, ISO 5807:1985, first edition (preview pages), International Organization for Standardization (iTeh Standards preview), Sections 9.1.1.2, 9.1.2.2 and 9.1.2.3 (shapes from the figures)
- Flowcharting Techniques, IBM Data Processing Techniques, Form C20-8152, International Business Machines Corporation (bitsavers.org), System flowcharts, Situation VI
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
Added .