8088 Juko ST RAM limit is too low
Closed this issue · 5 comments
What happened?
The 8088 Juko ST is supposed to be able to record up to 1024 kb of RAM during POST. However, 86Box's emulated board can't be configured beyond 640 kb. This prevents the use of a proprietary RAMDrive device and potentially other Juko programs as well.
This screenshot was taken from a YouTube video showing off the Juko ST's 1024 kb during POST :
Configuration file
[Hercules]
rgb_type = 2
blend = 1
[General]
vid_renderer = qt_software
force_43 = 1
vid_resize = 2
window_fixed_res = 1200x900
window_remember = 1
video_fullscreen_first = 0
sound_gain = 18
[Machine]
machine = jukopc
cpu_family = necv20
cpu_speed = 12000000
cpu_multi = 1
cpu_use_dynarec = 0
fpu_softfloat = 0
time_sync = local
mem_size = 640
[Video]
gfxcard = oti067
show_second_monitors = 0
[Input devices]
mouse_type = none
[Sound]
fm_driver = nuked
[Network]
net_01_link = 0
net_02_link = 0
net_03_link = 0
net_04_link = 0
[Ports (COM & LPT)]
lpt1_device = dot_matrix
[Storage controllers]
hdc = xtide_acculogic
cassette_mode = load
[Monitor #1]
window_coordinates = 248, 54, 1200, 900
[Monitor #2]
window_coordinates = 120, 120, 1200, 900
[WD1004A-WX1 MFM Fixed Disk Adapter]
bios_addr = C8000
base = 0320
irq = 5
[IBM CGA]
display_type = 0
composite_type = 0
rgb_type = 0
double_type = 3
snow_enabled = 1
[ST-11M MFM Fixed Disk Adapter]
base = 0320
irq = 5
bios_addr = C8000
revision = 5
[Floppy and CD-ROM drives]
fdd_01_image_history_01 = D:/Games/x86Box/Floppy/juko/juko.img
fdd_02_image_history_01 = D:/Games/x86Box/Floppy/lotussave.img
fdd_02_image_history_02 = D:/Games/x86Box/Floppy/Speedtst.IMG
fdd_01_image_history_02 = D:/Games/x86Box/Floppy/Games/stunt-car-racer/stunt.img
fdd_01_image_history_03 = D:/Games/x86Box/Floppy/Games/F152.img
fdd_02_image_history_03 = D:/Games/x86Box/Floppy/MSDos622/Disk 1 - Setup - 1.44mb.img
fdd_02_image_history_04 = D:/Games/x86Box/Floppy/MSDos622/newboot.img
fdd_01_image_history_04 = D:/Games/x86Box/Floppy/Games/003089_pub_pool/disk1.img
[PC/XT XTIDE]
bios = xt
[IBM EGA]
memory = 256
monitor_type = 6
[NCR NGA]
rgb_type = 0
snow_enabled = 1
memory = 64
charset = 2
[Video 7 VGA 1024i (HT208)]
memory = 512
[Trident TVGA 8900B]
memory = 256
[Realtek RTG3105 (ISA)]
memory = 512
[Sigma Color 400]
rgb_type = 4
enable_nmi = 1
bios_addr = C0000
[Colorplus]
display_type = 0
composite_type = 0
snow_enabled = 1
[Pravetz VDC-2]
display_type = 0
composite_type = 0
rgb_type = 5
double_type = 0
snow_enabled = 1
[Monster FDC Floppy Drive Controller]
bios_addr = D8000
[Iskra EGA (Cyrillic ROM)]
memory = 256
monitor_type = 9
[Xi8088]
turbo_setting = 1
bios_128kb = 1
umb_c0000h_c7fff = 0
umb_c8000h_cffff = 0
umb_d0000h_d7fff = 1
umb_d8000h_dffff = 0
umb_e0000h_e7fff = 0
umb_e8000h_effff = 0
[Compaq CGA 2]
display_type = 0
composite_type = 0
rgb_type = 5
double_type = 2
snow_enabled = 0
[Compaq CGA]
display_type = 0
composite_type = 0
rgb_type = 0
double_type = 3
snow_enabled = 1
[Hercules Plus]
rgb_type = 1
blend = 1
[Olivetti OGC (GO708)]
display_type = 0
composite_type = 0
rgb_type = 0
double_type = 3
snow_enabled = 1
[Tseng Labs ET4000AX (ISA)]
memory = 1024
bios_ver = v8_01
[Hard disks]
hdd_01_parameters = 17, 4, 306, 0, ide
hdd_01_fn = IDE_Type1.vhd
hdd_01_speed = 1989_3500rpm
hdd_01_ide_channel = 0:0
[SuperEGA]
memory = 256
monitor_type = 9
[AST SixPakPlus #2]
size = 64
start = 320
[AST SixPakPlus #3]
size = 64
start = 384
[AST SixPakPlus #4]
size = 64
start = 448
[AST SixPakPlus #1]
size = 512
start = 512
[Microsoft RAMCard for IBM PC #1]
size = 256
start = 624
[Paradise Systems 5-PAK #1]
size = 384
start = 576
[Paradise Systems 5-PAK]
irq = 2
[Everex EV-170 Magic I/O]
base = 0240
irq = 7
[Everex EV-159 RAM 3000 Deluxe #1]
size = 384
start = 640
length = 384
width = 0
speed = 0
ems = 1
base = 02E8
[Oak OTI-067]
memory = 256Operating system
Windows 11
CPU
Intel i3 13100F
86Box version
build 5671
Build architecture
Windows - x64 (64-bit)
Build type
- New recompiler
- Debug build
Download source
Official website (Jenkins, GitHub)
Additional context
No response
Ths means it must have some sort of proprietary EMS chipset, because with the top 384k reserved for ROM space, I doubt you can directly address 1024k of RAM using just the CPU.
It appears to be this: https://theretroweb.com/chipsets/943. Which means this is a CANTFIX, since the chipset has no datasheet.
After a little "investigation" I've found these info:
TAMCS00001-1.pdf
The PC supports 1MB RAM but the 384KB are for RAM Disk only
Drivers are here:
JUKO.zip
The file CDISK.SYS creates a 384KB RAM Disk
The drivers you provided don't work.
It seems not having the full 1024 kb in POST, like my initial screenshot shows, is causing issues.
is there a way to override the built-in 86Box RAM limits to test 1024kb of RAM?
I have these same drivers, one for a RAM drive, disk cache, and other for print spooler. But the 8088/8086 CPUs can only "see" 640kb of RAM unless the extra hardware chip is emulated. The 808x and 286 cannot map upper memory RAM in real mode without extra hardware. Some 286 can map it as XMS. But EMS, UMB or other type of management requires extra hard
ware.
The 386 uses the V86 mode to map some of the XMS RAM as EMS and/or UMB.