Abstract: A computer system is capable of easily and accurately executing an installation of an application program. A personal computer is provided with a CPU, a ROM, a RAM, an inputting device such as a keyboard and/or a mouse, a displaying device such as a display, an external storage media drive, which is connected with an external storage medium such as a CD-ROM (including a CD-R and a CD-R/W) and/or a DVD-ROM, for carrying out reading and writing of information between the external storage medium, a hard disk and a bus. An installer, which has a function of simultaneously displaying a manual of an application program stored in the external storage medium and an installation situation of the application program in the displaying device, is read in the RAM or the hard disk and executed when the application stored in the external storage medium is read out by the external storage media drive and installed in the hard disk.

Abstract: A gear shaving cutter, which is rotated in meshing engagement with a gear to be finished so as to impart a shaving finish to the latter, is formed upon its periphery with a plurality of cutting teeth, each of which is formed wholly or partially upon its cutting faces with two groups of grooves disposed to extend in two directions different from each other so as to thereby define therebetween lands having a generally rhombus or rhomboid configuration.