CTSS

CTSS-tan
Character Information
Common Names	CTSS-tan
Other Names	Compatible Time-Sharing System
Human Name(s)	Tessa Corbato
Faction	MIT Society
Lineage	MIT
Rival(s)	N/A
Appearance
Height	168 cm (5'6")
Hair Color	Dark red
Eye Color	Red/blue
Weapon(s)	N/A
Design
Creator	Bella
First Appearance	Dec 2007, overhauled 2025
Origin	OS-tan Collections
Technical Information
System Personified	Compatible Time-Sharing System
Developer(s)	MIT
Debut	Nov. 1961
Latest release	unknown, discontinued by 1973

Technical details

Developed by the MIT Computation Center and initially released in 1961, the Compatible Timesharing System was the first general purpose timesharing OS.

While it was only in use for twelve years across two installations (both on the MIT campus) CTSS heavily influenced the design of other early timesharing OSes. It debuted a number of modern operating system features, and multiple notable programs.

CTSS became usable under emulation as of 2010.

Character details

Physical

CTSS-tan is depicted as a woman in her 30s, average height with light olive skin, long dark red hair, red and blue eyes and thick oval glasses. Her travels have given her an appreciation for a wide variety of cultures, which she incorporates into her personal style, with long sleeve qipao-style dresses a favorite of hers. She favors the colors red and blue.

She has low vision and can read & write braille.

She speaks with a slight Bostonian accent.

Personality

A career academic, CTSS-tan is forward-thinking and hardworking, but modest about her accomplishments.

CTSS-tan is great at multitasking and can communicating with groups. She is good at understanding different perspectives, endearing her to both older and contemporary OS-tans.

She is a good mediator and lends a sympathetic ear to humans and computers alike, and while she gladly issues advice she pushes back gently on her reputation as "therapist". Because of her social experience, she comes off as an average human to those who aren't aware of her true nature.

Despite her talkative nature she's good at keeping secrets and dislikes gossip.

Can have a hot temper but is generally good at moderating it.

Powers

CTSS-tan possesses the power to be multiple places at once, the first OS-tan to have such. She is reluctant to discuss it, playing it off as good timing to those who aren't in the know.

History and background

CTSS-tan was born in Cambridge, Massachusetts in 1961. She traces part of her ancestry to the IBM 709 line, and part to Whirlwind-tan, who inspired her creation. While she is aware of her IBM kin and respects her grandmother IAS-tan, she takes strongly after Whirlwind-tan, whom she regards as her mother. CTSS-tan vowed to learn from both from Whirlwind-tan's successes and mistakes, surpassing the limitations that she faced as an early hardware-tan while inheriting her restless curiosity, optimism and hard work ethic.

CTSS-tan found employment as a librarian, translator and typesetter, working both at home and overseas. While accompanied by the typical coterie of an mainframe-tan of her time, she worked most closely with Selectric-kun. Atypically for an IBM, she was good terms with the early DEC-tans, and even employed PDP-7-tan.

A few years after her debut her first child, Multics-tan, was born. CTSS-tan personally attended to raising her, a full time job given Multics-tan's fragile health. Later, CP/CMS-tan, whose robustness warranted less involvement. Besides her children, CTSS-tan tutored a generation of timesharing OS-tans. ITS-tan among them, although she rebelled against her mentor's teachings and carved her own path.

CTSS-tan regarded Unix-tan highly despite Multics-tan's fraught relationship with her, and disapproved of the fighting between the two, though she was powerless to stop it.

Though she was in seemingly good health until the end of her life, she passed away suddenly in the early 1970s.

Theories and Notes

• May have been revived in modern times.
• May be acquaintances with EDSAC-tan.