GECOS-III supported both time-sharing (TSS) and batch processing, with dynamic allocation of memory (IBM had fixed partitions, at that time), making it a true second-generation operating system.

After Honeywell acquired GE's computer division, GECOS-III was renamed GCOS 3, and the hardware line was renamed to the Honeywell 6000 series, adding the EIS (enhanced instruction set, character oriented instead of word oriented).

[9] GCOS-62,[10][9] the operating system for another 32-bit low-end line of machines, the Level 62 series, was designed in Italy.

NEC supplied several generations of mainframe hardware at the high end, which would run both GCOS 8 and their own ACOS-4 Operating System.

This platform, called Novascale[13] and based on Itanium 2 processors, ran both Windows and Linux natively.

A trace of GCOS influence remains today in modern UNIX systems.

Some early Unix systems at Bell Labs used GCOS machines for print spooling and various other services.

TP8 used multiple static processes in a way similar to UNIX daemons to handle incoming transactions in a multiplexed way.

Systems running GCOS today use it mainly for batch and OLTP, or as a backend enterprise server.

It was also heavily influenced by projects such as MEDINET,[19] Multics, and WWMCCS,[20] and has inherited a strong security structure in consequence.

For a time separate versions of the GCOS system with special security features turned on were maintained specifically for government customers.

The top-level virtual memory architecture also simplifies sharing of code and data in a secure fashion, again in a way reminiscent of Multics.

[23] Documentation was printed pages, available on-premise to users (staff, students...), organized into steel binders, locked together in one monolithic steel reading rack, bolted to a table or counter, with pages organized for modular information updates, replacement, errata, and addenda.

[citation needed] Modern terminology for units of storage applies across various operating systems and computer vendors, and is part of everyday conversation.