VOGONS


First post, by zbiggy

User metadata
Rank Newbie
Rank
Newbie

Which type of mouse connection wastes less CPU/Computer resources?

Inport - a special ISA card with special mouse, does not hog CPU as bus mouse,
serial - ordinary older mouse connected to RS-232C port known as COM1
PS/2 - ordinary round mini plug with 6 pins. Very popular today.

Reply 2 of 5, by zbiggy

User metadata
Rank Newbie
Rank
Newbie
eL_PuSHeR wrote:

You forgot USB mice.

USB is not working in DOS.
USB is not present in older computers.
USB wastes the most CPU cycles and system resources in comparison to the other mouse types of connection (up to ~14% on modern machines are ate by usb mouse).

The CPU consumption of other mouse connections is unknown to Google.

Reply 4 of 5, by zbiggy

User metadata
Rank Newbie
Rank
Newbie

The best is PS/2 because:
-LPC chip on motherboard decodes the packets which mouse sends (as original i8042 keyboard & mouse controller does).
-As for hardware resources only rarely used IRQ12 is required for mouse (mouse uses i/o already used for keyboard: 60-64h).

serial mouse disadvantages:
-mouse sends raw packets to CPU. However transmission is hw accelerated by serial controller, but CPU must decode packets sent by mouse.
-COM port is wasted and its resources.

bus mouse disadvantages:
-CPU is polling ISA mouse card registers by every 30 or 60Hz (frequency depends on vertical refresh of screen so it can be 100Hz or 200Hz too) to check for mouse movement. Inport kind of such card is only probed when there is movement of mouse. This is optional feature of inport mouse which make it similar to PS/2 way of working. The i\o port and irq is required to work.

So it looks PS/2 is the best connector for mouse.

Reply 5 of 5, by dvwjr

User metadata
Rank Member
Rank
Member

Consider also that most of the mouse models sold today are only capable of being used as PS/2 or USB version. The days of the dual-mode mouse that could be used with serial ports and PS/2 ports are gone. To save money the cheap ones are PS/2 only. The better mouse models today are now USB connected - but getting mouse packets via the <ahem> wonderful USB protocol stack's overhead makes one wonder if the default 125 reports/sec are worth it...

Of course, the finest mouse Microsoft ever had built is one that they no longer acknowledge that they even made - the Intellimouse Pro. Since they stole the ergonomic design from a small company (Goldtouch Technologies) and got punished in court - it's like it never happened. 😳 Microsoft did a better job with their 'inspired' version that the Goldtouch original...

😁 I own two. 😁

dvwjr