Originally Posted by _kin_

SoftICE have at least two components ALL components load as standard
drivers:
1. siwvid.sys - mostly UI code load as SERVICE_BOOT_START driver

2. ntice.sys - SoftICE heart can load as SERVICE_BOOT_START but also
can load as SERVICE_SYSTEM_START or SERVICE_DEMAND_START drver

Most frequently ntice.sys configured as SERVICE_SYSTEM_START driver

3. Sometimes if ntice.sys load as SERVICE_BOOT_START it use third part:
siwsym.sys - SERVICE_BOOT_START driver where packed symbolic and config
info. This module used because in time when loaded SERVICE_BOOT_START drivers no file I/O services available (this drivers load by NTLDR).

P.S. Sorry for my poor english