The 155 had seven main memory choices, ranging from 256K to 2 MB; the 165: five possibilities, from 512K to 3 MB. Both models were described as having "a very high-performance buffer storage backed by a large" main memory.
Another signs of not being "the real 370 line" is that the main storage in 3155 was not using semiconductorsmonolithic, it was using the older type of iron core storage. The 3360 storage unit could have 256 or 512 KB of storage, each 3155 could have one to four 3360 units attached. Also, the microcode in 3155 was "hardwired" while later 370 systems loaded the microcode from a floppy disk, enabling easy upgrades. The 3155 also had very limited error logging capability and used a type writer console (3215).
