Server constructed with trays for hard disk modules

A server comprising:

• a bottom shell;
• a rear shell, connected to one end of the bottom shell;
• two side shells, connected to two sides of the bottom shell, wherein an opening is defined between the two side shells;
• a plurality of hard disk modules, positioned on the bottom shell;
• and
• a plurality of trays, wherein:
• a plurality of receiving channels are defined between the two side shells and communicating with the opening,
• the plurality of receiving channels are isolated and arranged side by side,
• the plurality of trays are received in the receiving channels,
• each hard disk module is positioned in each of the plurality of trays, and
• a front end of one of the two side shells and the rear shell defines at least one front connection port and at least one rear connection port for connecting cables of the hard disk module.