3.3 The Computer Case and Power Supply
3.3.3 Towers
Tower cases are usually designed to sit vertically on the floor beneath a desk. Some users in the past resorted to standing the desktop cases on their sides under the desk to provide more usable workspace on the desktop. This has prompted computer makers today to develop cases that would naturally fit under the desk. In general, tower cases typically have enough bays to hold floppy drives, CD-ROM drives, tape drives, DVD drives as well as just about anything else that might be installed. The internal design of a tower system resembles that of the desktop unit.

Tower cases come in three sizes:

  • Mid towers
  • Mini towers
  • Full-size towers

Mini-towers and mid-towers are shorter and less expensive than their full-size counterparts. There is one major drawback to choosing the smaller towers. There is little additional space for internal add-ons or disk drives, particularly if the mini-tower is chosen.

Many easy-access schemes have been built in to allow quick or convenient access to the inside of the system case. Some towers, for example, use removable trays that allow the motherboard and I/O cards to be plugged in before being slid into the unit. Other tower cases use hinged doors on the side of the case, allowing the system and I/O boards to swing away from the chassis. Either of these features will facilitate the process of assembling the computer.

It is important to note that the ventilation characteristics of some tower units tend to be poor. The cause of this is that the I/O cards are mounted horizontally. When the heat generated by the boards rises, it passes the upper boards, which are then subjected to additional heat. Thus, most tower cases include a secondary case fan to help increase the airflow and dissipate any excessive heat.