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Lenovo ThinkCentre M900 Tower (Yumbopeep)

Yumbopeep Front
ArcaOS license type


The Lenovo M900 tower computer is compatible with ArcaOS. Built-in video, sound, network, USB, serial port all function under ArcaOS 5.0. The computer features tool-free installation of SATA hard drives and an assortment of PCIe slots.


After you add the computer and optional CPU upgrade to the cart, proceed to the Accessories page to add PS/2 ports, parallel port, floppy drive, hard drive upgrade, IDE card or a USB 2.0 card.


PS/2 Ports

This computer has optional PS/2 ports.

PS/2 Ports

Yumbopeep PS/2 Ports

PS/2 Ports: $75.00 USD

Parallel Port

This computer has an optional parallel port.

Parallel Port

Parallel Port

Parallel Port: $50.00 USD

IDE Card

This PCIe-X1 bus card provides an internal IDE connection. You can use this card with DaniS506.ADD to provide support for Parallel ATA (PATA) hard drives.

IDE Card

Yumbopeep IDE Card

PCIe IDE Card: $75.00 USD

USB 2.0 Card

This PCIe-X1 bus card provides USB 2.0 ports. You can use this card with USBEHCD.SYS to provide support USB devices.

USB 2.0 Card

Yumbopeep USB 2.0 Card

PCIe USB 2.0 Card: $75.00 USD

USB Floppy Drive

This external USB Floppy drive can be used to read and write 720K and 1.44M 3 1/2 inch floppy disks.

USB Floppy Drive

USB Floppy Drive

USB Floppy Drive: $50.00 USD

External WiFi

Using a travel router with a desktop can free you from a wired Ethernet connection. I use the Mango Travel Router to access local WiFi or my phone's hot spot. Mango comes with everything you need to connect to an access point.

Mango Travel Router

Mango Thumbnail

Mango Travel Router: $65.00 USD

In the past, I have also used a TP-Link AC750 Wireless Travel Router, an Asus RP-N12 Wireless N300 Range Extender, and a TP-Link Nano Router. I include a folder of URL links to the admin pages of each of these routers to make it easy to set up the first time.

Instructions and details about external WiFi: Travel Routers

Hard drive upgrade

The hard drive can be upgraded to a 2 TB drive. Either a hard disk or an SSD is available to upgrade.

Hard drive upgrade

Yumbopeep hard drive upgrade
Storage type

Icy Dock dual removable SSD

The Icy Dock dual removable SSD allows mounting one or two SSD. The SSD can be ejected and replaced. Only SATA SSD are supported. The computer must be powered down before ejecting the disk or data loss can occur.

Icy Dock dual removable SSD

Icy Dock dual removable SSD<

Icy Dock dual removable SSD: $150.00 USD

Custom Orders

If you want to buy a customized version of this computer, fill out an order form and submit it to Blonde Guy. Blonde Guy will review your order and send you an invoice, payable using PayPal or any major credit card. If you prefer to pay by check, note that in the notes field of the order form, and I will e-mail you an invoice payable by check.

Enter the customizations you want on the computer in the notes portion of the order form.


Manufacturer: Model: ThinkCentre M900 Tower
Model number: 10FCS0AX00
Year introduced: 2015
CPU: Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
RAM: 8.0 GB
Hard drive: 1000 GB 3.5 inch SATA
Optional hard/solid state drive: 2000 GB SATA
Optical drive: Lenovo DVD-Multi player drive
Network: Intel Gigabit Ethernet using MultiMac32-E1000E driver
Audio: Intel audio with line out and line in using UniAud driver
USB ports: 8 (2 front, 6 back)
USB controllers: 0 UHCI, 0 OHCI, 0 EHCI, 1 XHCI
Video ports: VGA, DisplayPort

Physical Dimensions

Height: 16 inches
Width: 6.9 inches
Depth: 16.3 inches
Weight: 27.6 lbs

Power Consumption

Power consumption is 21 Watts, measured with the computer is booted to the desktop. With all CPU at 100%, the computer can consume about 60 watts. This computer consumes 1 Watt if it's plugged in, but switched off.

Disk Layout

The disk is partitioned to provide a bootable operating system volume and a bootable installer. Space is left for addtional bootable volumes. User data is stored on a separate volume.

This is the layout for the 1 TB HD. The Air-Boot boot manager is installed to select the volume to be started.

Volume NameDisk FormatDrive LetterVolume SizeDisk Name
ArcaOS-QJFS Q:10,009 MB1 TB
RecoveryFAT16 X:1,770 MB1 TB
Data JFS D:900,009 MB1 TB

This is the layout for the 2 TB SSD. The Air-Boot boot manager is installed to select the volume to be started.

Volume NameDisk FormatDrive LetterVolume SizeDisk Name
RecoveryFAT16 X:2,000 MB2 TB SSD
ArcaOS-FJFS F:10,001 MB2 TB SSD
ArcaOS-HJFS H:10,001 MB2 TB SSD
ArcaOS-QJFS Q:10,001 MB2 TB SSD
ArcaOS-PJFS P:10,001 MB2 TB SSD
Data JFS D:1,857,718 MB2 TB SSD

ArcaOS version

ArcaOS 5.0.7 (December 7, 2021) is the version used for this installation.

Performance Benchmarks

This table reports the SysBench 0.9.5 benchmarks for this computer. You can download SysBench 0.9.5 here:

PM-Graphics-marks 300
CPU integer-marks 16669
CPU floating point-marks 1150
DIVE-marks 11526
File I/O-marks 75970
Memory-marks 28642
Simultaneous I/O-marks 13
Disk I/O-marks 697

With 2 TB SSD...

PM-Graphics-marks 370
CPU integer-marks 16475
CPU floating point-marks 1162
DIVE-marks 16282
File I/O-marks 191222
Memory-marks 27174


Preloaded Software

Each Blonde Guy ArcaOS preloaded computer comes with a standard load of software. This page lists what is in the current pre-load. This list is updated over time to incorporate new essential OS/2 software as well as to keep up to date versions of existing software. When you receive your ArcaOS preloaded computer, you will have Blonde Guy's best installation of the latest OS/2 software.

Recovery DVD

The recovery DVD supplied is a bootable ArcaOS DVD with a backup of the hard drive as delivered. You can boot the machine from DVD, and perform maintenance functions. The maintenance folder is available on the recovery DVD. The factory backup is stored in the \Factory directory. The backups are simple zip files. You can use 7z or unzip to extract some or all of the files in a backup.

Build Notes

This section documents what I did to get this computer to work under ArcaOS. It is intended to show what goes into this computer, and also as a guide to the user who wants to build it himself.

BIOS changes

I upgraded the BIOS to BIOS Date: 06/23/2022; BIOS Revision: 1.191; Firmware: 1.21

BIOS settings

ArcaOS Installation

With eBay systems, it's best to do a throrough wipe of the hard disk before beginning. OS/2 and therefore ArcaOS, is very picky about drive geometry. A disk laid out by any other operating system will likely not work under OS/2.

I prefer to let Disk Utility on the ArcaOS installation CD do all the work. I boot the DVD, get to the start screen. I pick System Management, and then Disk Utility. This will have several possible outcomes.

If it does not find the disk at all, then perhaps the disk is is partitioned using GPT instead of MBR. The remedy for this is described on the following web page.

Installing ArcaOS over Windows 10

A second possibility is that Disk Utility finds the disk, but does not find valid formatting. In this case the following screen will appear. In this case I simply allow Disk Utility to fix the problem, and reboot.

Disk Utility

** Problems were detected in your disk layout. The problems are listed below.

We may be able to fix these problems for you; see below for details. Please note, however, that we cannot be held liable for any damage or lost data that may result from this action.

The following problems were found:

* There is no valid partition table on the disk. A new partition table must be written before this disk can be used.The disk appears to contain no data, so this operation should be harmless. However, if it does contain data which OS/2 has failed to detect, any such data will be lost if you proceed.

The above problem(s) must be fixed before you can use this disk with OS/2.

If I have fixed the disk using DiskUtility or other procedure, then I run Disk Utility again. If it says "No problems found.", then I proceed to lay out the disk paritioning that I want using "Manage Volumes (Graphical)."

Once volumes are laid out, I can proceed to install ArcaOS, or use the Blonde Guy Recovery DVD to restore a backed up ArcaOS installation.

Driver Notes

With the new 12.07 USB drivers that come with ArcaOS 5.0.5, USB 3.0 is working well for mouse and keyboard, even through my KVM. USB sticks now mount successfully. USB sticks can be supported even without an optional USB 2.0 add-in card.

The Disk driver is OS2AHCI with native command queueing enabled. UniAud works.


DOS Full-Screen works. Alt-Home from a DOS Full-Screen then allows a DOS Window to work.



Yumbopeep Front


Yumbopeep Rear

Interior shot with tool-free drive bays.

Yumbopeep Interior

Expansion slots

Yumbopeep Slots