PC DOS 4.01 was released in August 1988. This maintenance release is only about one month older than PC DOS 4.00. Contrast this with MS-DOS 4.01, which was released in April 1989.
Directory Listings of the two 720Kb distribution diskettes are provided below.
[PCjs Machine "ibm5170-pcdos401"]
Waiting for machine "ibm5170-pcdos401" to load....
Volume in drive A has no label
Directory of A:\
IBMBIO COM* 32816 8-03-88 12:00p
IBMDOS COM* 36000 8-03-88 12:00p
AUTOEXEC BAT 39 6-17-88 12:00p
ANSI SYS 9148 6-17-88 12:00p
COMMAND COM 37637 6-17-88 12:00p
CONFIG SYS 96 6-17-88 12:00p
COUNTRY SYS 12838 6-17-88 12:00p
DISKCOPY COM 10428 6-17-88 12:00p
DISPLAY SYS 15741 6-17-88 12:00p
DRIVER SYS 5274 6-17-88 12:00p
FASTOPEN EXE 16302 6-17-88 12:00p
FDISK COM 70151 6-17-88 12:00p
FORMAT COM 22923 6-17-88 12:00p
IFSFUNC EXE 21653 8-03-88 12:00p
KEYB COM 14759 6-17-88 12:00p
KEYBOARD SYS 23360 8-03-88 12:00p
MODE COM 23056 8-03-88 12:00p
PRINTER SYS 18946 6-17-88 12:00p
REPLACE EXE 17199 6-17-88 12:00p
SELECT DAT 22453 8-03-88 12:00p
SELECT EXE 99545 8-03-88 12:00p
SELECT HLP 27562 8-03-88 12:00p
SELECT PRT 1594 8-03-88 12:00p
SHARE EXE 10301 8-03-88 12:00p
SYS COM 11472 6-17-88 12:00p
VDISK SYS 6376 6-17-88 12:00p
XCOPY EXE 17087 6-17-88 12:00p
XMA2EMS SYS 29249 8-03-88 12:00p
XMAEM SYS 19312 6-17-88 12:00p
EGA CPI 49052 6-17-88 12:00p
LCD CPI 10592 6-17-88 12:00p
4201 CPI 6404 6-17-88 12:00p
4208 CPI 641 6-17-88 12:00p
5202 CPI 402 6-17-88 12:00p
012345 678 109 6-17-88 12:00p
DOS00I 400* 0 6-17-88 12:00p
36 file(s) 700517 bytes
17408 bytes free
Volume in drive A has no label
Directory of A:\
APPEND EXE 11186 8-03-88 12:00p
ASSIGN COM 5785 6-17-88 12:00p
ATTRIB EXE 18247 6-17-88 12:00p
BACKUP COM 33754 6-17-88 12:00p
BASIC COM 1065 6-17-88 12:00p
BASICA COM 36285 6-17-88 12:00p
CHKDSK COM 17771 6-17-88 12:00p
COMP COM 9491 6-17-88 12:00p
DEBUG COM 21606 6-17-88 12:00p
DISKCOMP COM 9889 6-17-88 12:00p
DOSUTIL MEU 6660 6-17-88 12:00p
EDLIN COM 14249 6-17-88 12:00p
FILESYS EXE 11125 6-17-88 12:00p
FIND EXE 5983 6-17-88 12:00p
FORMAT COM 22923 6-17-88 12:00p
GRAFTABL COM 10271 6-17-88 12:00p
GRAPHICS COM 16733 6-17-88 12:00p
GRAPHICS PRO 9413 6-17-88 12:00p
JOIN EXE 17457 6-17-88 12:00p
LABEL COM 4490 6-17-88 12:00p
MEM EXE 20133 6-17-88 12:00p
MORE COM 2166 6-17-88 12:00p
MORTGAGE BAS 6207 6-17-88 12:00p
NLSFUNC EXE 6910 6-17-88 12:00p
PCIBMDRV MOS 295 6-17-88 12:00p
PCMSDRV MOS 961 6-17-88 12:00p
PCMSPDRV MOS 801 6-17-88 12:00p
PRINT COM 14024 8-03-88 12:00p
RECOVER COM 10732 6-17-88 12:00p
REPLACE EXE 17199 6-17-88 12:00p
RESTORE COM 40030 6-17-88 12:00p
SHELL CLR 4438 6-17-88 12:00p
SHELL HLP 65667 8-03-88 12:00p
SHELL MEU 4588 8-03-88 12:00p
SHELLB COM 3937 8-03-88 12:00p
SHELLC EXE 154377 8-03-88 12:00p
SORT EXE 5914 6-17-88 12:00p
SUBST EXE 18143 6-17-88 12:00p
TREE COM 6334 6-17-88 12:00p
DOS01L 400* 0 6-17-88 12:00p
40 file(s) 667239 bytes
51200 bytes free