Multi-mode computing systems for point of sale transactions

A computing system comprising:

• a first housing;
• a processing device disposed in the first housing;
• a user interface and a first input/output interface integrated with the first housing and in communication with the processing device, the first input/output interface configured to receive power for delivery to the processing device;
• a second housing configured to carry the first housing;
• an attachment mechanism configured to selectively attach together the first housing and the second housing for carry of the first housing by the second housing;
• a second input/output interface configured to be communicatively coupled to the first input/output interface when the first housing and the second housing are attached;
• a power source integrated into the second housing and connected to the second input/output interface for delivery of power to the processing device via the first input/output interface;
• wherein the second housing comprises a cover member mechanically engaged with the attachment mechanism, and configured to be positioned in either a first position or a second position;
• wherein in the first position, the cover member interacts with the attachment mechanism to detach the first housing from the second housing;
• and
• wherein in the second position, the cover member covers the first and second input/output interfaces.