IS-DOS  iS-DOS is a disk operating system for Russian ZX Spectrum clones. iS-DOS has been developed in 1990 or 1991, by Iskra Soft (Leningrad, USSR). It handles floppy disks (double sided, with double density), hard disks, and CD-ROM. Maximum iS-DOS partition size on a hard disk is 16 MiB. Unlike TR-DOS, iS-DOS is a RAM-based operating system, which reduces amount of memory for user programs.  iS-DOS Chic is a version developed for Nemo KAY. It provides more memory for user programs. TASiS is a modern version developed by NedoPC for ATM Turbo 2+ in 2006. It supports text mode and high memory of this machine. It is based on iS-DOS Chic.