Terminal modes and available terminals
The Linux® terminals that are provided by the console device drivers include line-mode terminals, block-mode terminals, and full-screen mode terminals.
On a full-screen mode terminal, pressing any key immediately results in data being sent to the terminal. Also, terminal output can be positioned anywhere on the screen. This feature facilitates advanced interactive capability for terminal-based applications like the vi editor.
On a line-mode terminal, the user first types a full line, and then presses Enter to indicate that the line is complete. The device driver then issues a read to get the line, adds a new line, and hands over the input to the generic TTY routines. Line-mode terminals provide fewer capabilities than full-screen or block mode terminals and are intended as a backup for emergencies.
The terminal that is provided by the 3270 terminal device driver is a traditional IBM® mainframe block-mode terminal. Block-mode terminals provide full-screen output support and users can type input in predefined fields on the screen. Other than on typical full-screen mode terminals, no input is passed on until the user presses Enter. The terminal that is provided by the 3270 terminal device driver provides limited support for full-screen applications. For example, the ned editor is supported, but not vi.
Table 1 summarizes when to expect which terminal mode.
| Accessed through | Environment | Device driver | Mode |
|---|---|---|---|
| Operating System Messages applet on the HMC | LPAR | SCLP line-mode terminal device driver | Line mode |
| z/VM® emulation of the HMC Operating System Messages applet | z/VM | SCLP line-mode terminal device driver | Line mode |
| Integrated ASCII Console applet on the HMC | z/VM or LPAR | SCLP VT220 terminal device driver | Full-screen mode |
| KVM host (for example, using the virsh console command) | KVM | SCLP line-mode terminal device driver | Line mode |
| KVM host (for example, using the virsh console command) | KVM | SCLP VT220 terminal device driver | Full-screen mode |
| 3270 terminal hardware or emulation | z/VM with
CONMODE=3215 or KVM |
3215 line-mode terminal device driver | Line mode |
| 3270 terminal hardware or emulation | z/VM with
CONMODE=3270 or KVM |
3270 terminal device driver | Block mode |
| iucvconn program | z/VM | z/VM IUCV HVC device driver | Full-screen mode |
| KVM host (for example, using the virsh console command) | KVM | virtio-console device driver | Full-screen mode |
The 3270 terminal device driver provides three different views.