Information Management Systems and Services provides academic computing services at Caltech. An IMSS account is a username and password associated with your real name and your Caltech UID number, granting you authorized access to IMSS computing services, including email, as listed at
https://www.imss.caltech.edu/

All students are provided with an IMSS account; as a courtesy service, IMSS accepts username preferences from students prior to creating the accounts in late summer. If you do not provide your username preferences, or the usernames you request are already in use, IMSS will assign a username for you, based on your real name.

Instructions for submitting your preferences are located at https://www.imss.caltech.edu/ .