Hi,
Libretto also had a bigger dock (PA2718U) with additional PCMCIA on the bottom, so you could probably use both of them (but I actually didn't try it). I'm not sure if PCMCIA CD drive would work in DOS without special drivers. Probably these laptops just came with preinstalled OS. It is also possible to install Windows 95 straight out of floppies (50CT and 70CT were released before Windows 98). You can also boot off floppy disk, format the drive copying system files, (format c: /s), copy CD-rom driver to C: drive, then disconnect floppy drive and plug plug CD drive, reboot. You should be able to boot off hard disk, access CD drive and run setup.

Edit: here is more info https://www.mail-archive.com/libretto@basicli … m/msg02907.html

How to use Panasonic KXL810A or Other Third Party External CD-ROM with the Toshiba Recovery CD Libretto 100CT, 110CT or later + […]
Show full quote

How to use Panasonic KXL810A or Other Third Party External CD-ROM with the
Toshiba Recovery CD Libretto 100CT, 110CT or later + Portege 320CT, 3010CT,
7000/7010CT or later

Toshiba supplies Recovery CD's with some ultra-portable computers w/o
integrated CD-ROM drives such as the Portege and Libretto series. To use the
recovery CD for these models, customers must either have a compatible
Toshiba CD-ROM docker or one of the third party external CD-ROM drives (EXP
Traveler, Trantor or BusToaster SCSI) supported by the Recovery CD boot
diskette. Other third party external CD-ROM drives are not supported by the
Recovery CD boot diskette so recovery to factory pre-installed software is
not possible.
Procedure:
This information shows an example of how to create a recovery boot diskette
for the Panasonic KXL-810A portable CD-ROM drive, so users can restore the
factory pre-installed software using the recovery CD. The same steps can be
used to create recovery CD boot diskettes for similar third party external
CD-ROM drives. The following procedures will work for the following models:

Libretto 100CT, 110CT or later
Portege 320CT, 3010CT, 7000/7010CT or later

The Panasonic KXL-810A portable CD-ROM drive should include the drive itself
and a PCMCIA CD-ROM Interface card (bundled with KXL-810A). Follow these
steps to create a boot diskette:

1.Insert a blank floppy disk into any computer running DOS 6.22 or later, or
Windows 95.
2.Use "FORMAT A:/S" command to format the disk and copy system files.
3.Create the following directories on the floppy disk;

A:\CDROM
A:\DOS

4.Copy the following files into the A:\CDROM directory. These files should
be located on Panasonic KXL-810A driver disk or may be obtained from
Panasonic.

ASPIO365.SYS
KMECD.SYS

Copy the following DOS files into the A:\DOS directory. These files can be
located in the DOS directory of the same computer used to create the boot
diskette.

HIMEM.SYS
MSCDEX.EXE
SETVER.EXE
FDISK.EXE
FORMAT.COM

5.Create a Config.sys and Autoexec.bat file on the boot diskette as follows:

[CONFIG.SYS]

DEVICE=A:\DOS\HIMEM.SYS /TESTMEM:OFF
DOS=HIGH,UMB
DEVICEHIGH=A:\DOS\SETVER.EXE
DEVICE=A:\CDROM\ASPIO365.SYS /port=300 /mem=CE00
DEVICE=A:\CDROM\KMECD.SYS /D:PCMCIACD /n:1

[AUTOEXEC.BAT]

@ECHO OFF
PATH=A:\;A:\CDROM
A:\DOS\MSCDEX.EXE /D:PCMCIACD /L:Q

After the boot diskette has been created, use these steps to restore the
software.

6.Attached the Panasonic KXL-810A CD-ROM drive to the Toshiba computer
PCMCIA slot via the PCMCIA CD-ROM Interface card.

7.Insert Toshiba Recovery CD into Panasonic CD-ROM drive. Boot up computer
using this boot disk. The CD-ROM should now be configured as the "Q" drive.

8.At the DOS prompt type "CD\DOS" and press the "Enter" key to Click DOS
directory. Repartition/format the hard drive first using the fdisk and
format commands.

9.At the DOS prompt type "Q:" and press the "Enter" key to Click drive Q
from drive A.

10.At the DOS prompt type "CD\BIN" and press the "Enter" key to Click BIN
directory.

11.At the DOS prompt type the word "RECOVERY" and press the "Enter" key to
start the recovery process.

To create boot diskettes for different third party external CD-ROM Drives,
simply replace the driver files under A:\CDROM and modify the Config.sys
statements accordingly