TNS HC-08

Also called Home computer 8bit.It was manufactured from 1988 by JZD AK Slušovice. The computer was inspired by or was successor to TNS GC. Hardware is based on U880D @ 3 MHz.Operating system running on the computer: TNS-DOS(TurboDOS).

Parts of this topic may be machine translated.

price from 25,000 CZK

Connectable to the TNS-NET network, the HC-08 enables system booting over the network.

Keyboard identical to TNS HC-16.

Variants

• TNS HC: basic variant, for connection to the TNS-NET network
• TNS HCF: mini-floppies
• TNS HCC: coupler
• TNS HCFC: coupler+flp

Periphery

• Mouse Tesla 3WN 16605
• 320 KB of RAM

BootROMs

A total of 3 variants have survived:

• Network Bootloader HC-8 V 1.2 (RL) Slušovice Software 1988
• 2048 bytes CRC-32 2F0D5716
• Loader TNS (FWL) - in 1.0 JZD Slušovice 1989
• 2x 2048 bytes MD5: 1.0: c82a94264d590e60c2f3fff992a4affc rom1.bin + f6e39746e474850c3bb8451c4954ed26 rom2.bin
• Loader TNS (FWLP) - in 1.2 JZD Slušovice 1989
• 2x 2048 bytes MD5: 12504d6db4e44800d3912a7caa0070a7 hc08rom12_TNSROM1.BIN + 4be12ee31684fc48c9d32f425b82618f hc08rom12_TNSROM2.BIN

For variants with two 2716 memories, the first is from address 0x0000, the second from address 0x1000 (i.e. there is a gap, apparently due to the plan for a larger circuit). The code first copies the contents to RAM, then the ROM is disconnected from the memory range.

Description from documentation

With TNS-HC computers, it is possible to install the operating system either from 5 1/4" floppy disks that are directly connected to it, or within the network via a fast or slow line from another computer in the network.

By the term "fast line connection" we mean the connection of TNS computers with a coaxial cable using UPP-NET modules.

By the term "slow line connection" we mean a serial current loop - channels A and B, controlled by the ASK or QASK module.

Channel A current loop and fast line are controlled by a common technical device and it only depends on the setting of the switches in the TNS-HC computer which one will be controlled. For this reason, they cannot be connected at the same time.

After turning on the computer, or resetting it, the bootloader reports by displaying the initial header and then starts to independently check whether there is a diskette in any of the disk drives. It first tests drive 0, then 1. If it actually finds the diskette, it tries to load a special boot program from it, which is usually stored in the reserved tracks of each system diskette. If the disk found is indeed a system disk, the operating system will be loaded. Otherwise, the attempt to install the system will be unsuccessful (it will "freeze").

If the bootloader does not find a diskette in any disk drive, it will ask where to boot the system from:

xxx asks where to boot from (A,B,L,X,Y,0-31 + Take) ?

The value "xxx" is the number of the given TNS-HC computer set by the switch.

The user is expected to enter one of the following options:

A - the bootloader will attempt to boot the operating system from disk drive 0.

B - the bootloader will attempt to boot the operating system from disk drive 1.

F - the bootloader tries to boot the operating system first from disk drive 0. If it does not find a diskette in this drive, it tries to boot the system from drive 1 as well.

X - the bootloader switches to channel A of the current loop

Y - loader switches to channel B of the current loop

L - the bootloader switches to fast line. This state is set by default.

dd - the number under which the remote computer from which the system will be loaded is known in the network. It is entered decimally in the range 0 - 31.

If you make a mistake when entering an option, you can correct yourself using the [<-] key.

When booting from a remote computer, it is first necessary to determine whether the operating system will be booted from a fast or slow link and, if necessary, determine the current loop channel. As already mentioned, by default it is set to boot from the fast line, which is used most often. We mark the line by selecting L, X or Y. The bootloader prepares for booting from the required line and asks again where to boot the operating system from. However, it is now expecting to enter the number of the remote computer from which the system will be booted.

The bootloader always tries to boot the operating system from floppy disks first. However, so that we do not have to wait for the bootloader to detect that there are no floppy disks inserted in the disk drives when booting from the line, we can press the desired option at the same time as pressing the [RESET] button. After releasing both buttons, the bootloader will try to boot the system according to our request.

Examples

📋Loader TNS (FWLP) - in 1.2 JZD Slušovice 1989


Floppy 0
Floppy 1
003 asks where to introduce (A,B,0-31 + Take) ? 2
The line is connecting...ok
reading the operating system ... ddd
I'm handing over control to OS

After turning on the computer, or resetting it, the bootloader displayed its initial header and started to check whether there are floppies inserted in the disk drives. It follows this sequence even though the 5 1/4" drives are not physically connected to the computer. However, the bootloader asked where to boot from, which suggests that it did not find the floppies in the drives. We require booting via the default fast line from computer number 2. The bootloader first tried to see if the connection could be established, so it started loading its own system file, SYS.SYS. handed over control of the system.

2) Loader TNS (FWLP) - in 1.2 JZD Slušovice 1989

Floppy 0 boots OSBOOT

OSBOOT V 2.01 (C) SWS/TPS Slusovice

Now the bootloader has found a system diskette in disk drive 0, which we can tell by the fact that it managed to boot the special OSBOOT boot program from the diskette. He first wrote out his header and then looked for the system file SYS.SYS on the diskette, which he handed over after the control was introduced.

3) Loader TNS (FWLP) - in 1.2 JZD Slušovice 1989

Floppy 0

Floppy 1 boots OSBOOT

The bootloader tested for diskettes in the drives. It didn't find the disk in drive 0, it did in drive 1. However, it is not a system disk because the bootloader failed to boot the special OSBOOT boot program from it. The only solution to this error condition is to reset the computer.

4) Loader TNS (FWLP) - in 1.2 JZD Slušovice 1989

Floppy 0 boots OSBOOT

OSBOOT V 2.01 (C) SWS/TPS Slusovice

SYS.SYS not found

Even in this case, the diskette inserted in drive 0 is not system because it does not contain the system file SYS.SYS.

5) Loader TNS (FWLP) - in 1.2 JZD Slušovice 1989

Floppy 1 selection error

In this case, we already requested to boot from drive 1 during the computer reset. We pressed the [RESET] and [B] buttons at the same time. We can tell this from the fact that the bootloader tried to boot immediately from the diskette in drive 1 without first testing drive 0. However, since there was no system diskette in that drive, the bootloader gave an error message.

6) Loader TNS (FWLP) - in 1.2 JZD Slušovice 1989

011 asks where to introduce (A,B,0-31 + Take) ? 5

The line is establishing a connection... - communication error

011 asks where to introduce (A,B,0-31 + Take) ?

The first thing that can be deduced from the texts in this example is that we already requested to boot the system via fast line during the reset. We pressed the [RESET] and [L] buttons at the same time. The bootloader tried to establish a connection but failed. In this case, look for the fault directly on the line.

7) Loader TNS (FWLP) - in 1.2 JZD Slušovice 1989

Floppy 0

Floppy 1

008 asks where to introduce (A,B,0-31 + Take) ? 1

The line is connecting...ok

reading operating system ... 000

If the bootloader succeeds in establishing a connection, it tries to load the system file SYS.SYS. If the file is not loaded (the counter remains zero), the problem must be looked for directly on the computer from which the system is to be booted.

I/O ports

Chipselect signals are generated by 74154 (IC104)

Computers derived from TNS HC-08

The following computers were inspired by or derived from TNS HC-08:

• TNS HC-16 (JZD AK Slušovice)

References

• Kolektiv aut.: ASSEMBLER Z-80 ; II. vydání - Slušovice 1987
• Ing. M. Muselík: Systémový popis mikroprocesoru Z80 (technika + programování) ; Slušovice 1982
• P. Dvořák a kol.: Mikroprocesorový systém Z80 ; TESLA VÚST 1981 interní zpráva
• Ing. P. Valášek, CSc.: Mikroprocesor 8080 a jeho základní obvody, Svazek 2, díl 1; Knižnice ČSVTS - 1986
• J. Neštický a kol.: Stavebnice Z 80 ; Slušovice ....
• https://www.youtube.com/watch?v=iPhmtdLzlNg (WebArchive)