- X
- X16CLK
- X1CLK
- X32CLK
- X64CLK
- XCASE
- XCT
- XD_CONTROL
- XD_DATA
- XD_GEOMETRY
- XD_INFO
- XD_JUMPER
- XD_MAXDRIVES
- XD_RESERVED
- XD_RESET
- XD_RETRIES
- XD_SELECT
- XD_SIGNATURE
- XD_STATUS
- XD_TIMEOUT
- XENIX_LINK_MAX
- XENIX_NICFREE
- XENIX_NICINOD
- XENIX_SUPER_MAGIC
- XIAFS_ADDRS_PER_Z
- XIAFS_ADDRS_PER_Z_BITS
- XIAFS_BITS_PER_Z
- XIAFS_BITS_PER_Z_BITS
- XIAFS_GET_BLOCKS
- XIAFS_INODES_PER_Z
- XIAFS_PUT_BLOCKS
- XIAFS_ZSHIFT
- XIAFS_ZSIZE
- XIAFS_ZSIZE_BITS
- XKPHYS
- XKSEG
- XKSSEG
- XKUSEG
- XMIT_1_RETRY
- XMIT_BEACON
- XMIT_BUFF
- XMIT_BUFF_SIZE
- XMIT_DATA_REQ
- XMIT_DEF
- XMIT_DIR_FRAME
- XMIT_END
- XMIT_ERR
- XMIT_LCAR
- XMIT_LCOL
- XMIT_OWN
- XMIT_RESERV
- XMIT_RETRY
- XMIT_RTRY
- XMIT_START
- XMIT_TDRMASK
- XMIT_TEST_CMD
- XMIT_UFLO
- XMIT_UI_FRAME
- XMIT_XID_CMD
- XMTU
- XMT_BAR
- XMT_CHAIN
- XMT_CMD
- XMT_COUNT
- XMT_Chain_ErrStop
- XMT_Chain_Int
- XMT_HEADER
- XMT_LOWER_LIMIT
- XMT_LOWER_LIMIT_REG
- XMT_RAM
- XMT_STATUS
- XMT_UPPER_LIMIT
- XMT_UPPER_LIMIT_REG
- XSIG_LL
- XTABS
- XTAL
- XTALFREQ
- XT_DISK_MAJOR
- Xmit_pkt
- Xmit_resp
- Xsig
- XsigH
- XsigL
- XsigLL